Water Column Gauges | McMaster-Carr

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Pounds per Square Inch

For Use With

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Measures

Differential Pressure

Differential Vacuum

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Pressure Numeric Increments

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Pressure Scale Range

Maximum Pressure

Less than 100 in. H₂O

100 in. H₂O to 249 in. H₂O

250 in. H₂O to 499 in. H₂O

500 in. H₂O to 999 in. H₂O

1,000 in. H₂O or greater

Connection Material

Pipe Size

Connects To

Minimum Pressure

Graduations

Maximum Environment Temperature

Gender

Maximum Temperature

Maximum Process Temperature

Material

Minimum Temperature

U.S.–Mexico–Canada Agreement (USMCA) Qualifying

Yes

REACH

Compliant

DFARS Specialty Metals

Exempt

Export Control Classification Number (ECCN)

RoHS

Pressure Resolution

Indicating Liquid Color

98 Products

About Pressure Gauges

Find a gauge with the right connection material and dial type—many with traceable calibration certificates.

Low-Pressure Differential Gauges with U-Tube

Also known as manometers, these gauges come with indicating liquid that moves up and down two columns—the difference in height between them is your pressure. They are commonly used to indicate clogged filters.

316 Stainless Steel Connections (Inches of Water)

Image of Product. Front orientation. Differential Pressure Gauges. Low-Pressure Differential Gauges with U-Tube, 316 Stainless Steel Connection.

							Environment Temperature Change, ° F		Process Temperature Range, ° F			Mounting
	Pressure, in. H₂O	Pressure Scale Range	Pressure Numeric Increments, in. H₂O	Graduations, in. H₂O	Max. Pressure, psi	Ht.	Min.	Max.	Min.	Max.	Mount Type	Fasteners Included	Hole Dia.	No. of	For Use With	Accuracy		Each
1/4 NPT Female Threaded Pipe Connection



		0 to 10	5-0-5 In. of H₂O	1	0.1	250	14"	35	150	35	250	Screw On	No	3/16"	4	Air, Carbon Dioxide, Argon, Acetylene, Steam	Not Rated	4044K32	0000000


		0 to 15	7-0-7 In. of H₂O	1	0.1	250	18"	35	150	35	250	Screw On	No	3/16"	4	Air, Carbon Dioxide, Argon, Acetylene, Steam	Not Rated	4044K33	000000

Nylon Connections (Inches of Water)

Image of Product. Front orientation. Differential Pressure Gauges. Low-Pressure Differential Gauges with U-Tube, Nylon Connection.

Barbed Fitting Connection—Gauges with barbed tube connection have a flexible body that rolls up for storage or transport.

Magnet Mount—Magnet-mount gauges can be moved for use in multiple locations.

							Environment Temperature Change		Process Temperature Range
	Pressure, in. H₂O	Pressure Scale Range	Pressure Numeric Increments, in. H₂O	Graduations, in. H₂O	Max. Pressure	Ht.	Min.	Max.	Min.	Max., ° F	Mount Type	For Use With	Accuracy		Each
Male Barbed Tubes for 3/16" Tube IDs



		0 to 8	4-0-4 In. of H₂O	1	0.1	Not Rated	17"	Not Rated	Not Rated	Not Rated	130	Magnet	Air, Carbon Dioxide, Hydrogen, Argon	Not Rated	3986K11	0000000


		0 to 12	6-0-6 In. of H₂O	1	0.1	Not Rated	21"	Not Rated	Not Rated	Not Rated	130	Magnet	Air, Carbon Dioxide, Hydrogen, Argon	Not Rated	3986K12	000000
		0 to 16	8-0-8 In. of H₂O	1	0.1	Not Rated	25"	Not Rated	Not Rated	Not Rated	130	Magnet	Air, Carbon Dioxide, Hydrogen, Argon	Not Rated	3986K13	000000
		0 to 24	12-0-12 In. of H₂O	1	0.1	Not Rated	33"	Not Rated	Not Rated	Not Rated	130	Magnet	Air, Carbon Dioxide, Hydrogen, Argon	Not Rated	3986K14	000000
		0 to 30	15-0-15 In. of H₂O	1	0.1	Not Rated	39"	Not Rated	Not Rated	Not Rated	130	Magnet	Air, Carbon Dioxide, Hydrogen, Argon	Not Rated	3986K15	000000
		0 to 36	18-0-18 In. of H₂O	1	0.1	Not Rated	45"	Not Rated	Not Rated	Not Rated	130	Magnet	Air, Carbon Dioxide, Hydrogen, Argon	Not Rated	3986K16	000000
		0 to 48	24-0-24 in of H₂O	1	0.1	Not Rated	57"	Not Rated	Not Rated	Not Rated	130	Magnet	Air, Carbon Dioxide, Hydrogen, Argon	Not Rated	3986K17	000000
		0 to 60	30-0-30 In. of H₂O	1	0.1	Not Rated	69"	Not Rated	Not Rated	Not Rated	130	Magnet	Air, Carbon Dioxide, Hydrogen, Argon	Not Rated	3986K18	000000
		0 to 72	36-0-36 In. of H₂O	1	0.1	Not Rated	81"	Not Rated	Not Rated	Not Rated	130	Magnet	Air, Carbon Dioxide, Hydrogen, Argon	Not Rated	3986K19	000000

Brass Connections (Inches of Water)

Magnet Mount—Magnet-mount gauges can be moved for use in multiple locations.

							Environment Temperature Change		Process Temperature Range
	Pressure, in. H₂O	Pressure Scale Range	Pressure Numeric Increments, in. H₂O	Graduations, in. H₂O	Max. Pressure, psi	Ht.	Min.	Max.	Min.	Max.	Mount Type	For Use With	Accuracy		Each
Female Compression Tubes for 1/4" ODs



		0 to 8	4-0-4 In. of H₂O	1	0.1	100	20"	Not Rated	Not Rated	Not Rated	Not Rated	Magnet	Air, Carbon Dioxide, Hydrogen, Argon	Not Rated	3985K41	0000000


		0 to 12	6-0-6 In. of H₂O	1	0.1	100	25"	Not Rated	Not Rated	Not Rated	Not Rated	Magnet	Air, Carbon Dioxide, Hydrogen, Argon	Not Rated	3985K42	000000
		0 to 16	8-0-8 In. of H₂O	1	0.1	100	30"	Not Rated	Not Rated	Not Rated	Not Rated	Magnet	Air, Carbon Dioxide, Hydrogen, Argon	Not Rated	3985K13	000000
		0 to 20	10-0-10 In. of H₂O	1	0.1	100	34"	Not Rated	Not Rated	Not Rated	Not Rated	Magnet	Air, Carbon Dioxide, Hydrogen, Argon	Not Rated	3985K14	000000
		0 to 24	12-0-12 In. of H₂O	1	0.1	100	39"	Not Rated	Not Rated	Not Rated	Not Rated	Magnet	Air, Carbon Dioxide, Hydrogen, Argon	Not Rated	3985K15	000000
		0 to 36	18-0-18 In. of H₂O	1	0.1	100	58"	Not Rated	Not Rated	Not Rated	Not Rated	Magnet	Air, Carbon Dioxide, Hydrogen, Argon	Not Rated	3985K17	000000

Low-Pressure Differential Gauges with Dial Indicator

Measure small changes in air pressure with these gauges. They are commonly used to indicate clogged filters and to monitor fans and blowers.

Aluminum Case with Aluminum Connections—Single Scale (Inches of Water)

	Dial Dia.	Pressure Numeric Increments, in. H₂O	Graduations, in. H₂O	Environment Temp. Range, ° F	Process Temp. Range, ° F	Features	Includes	For Use With	Accuracy		Each
1/8 NPT Female Threaded Pipe Connection



	0 to 0.25	4"	0.05	0.005	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±4	4021K12	000000


	0 to 0.5	4"	0.1	0.01	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±3%	4021K13	00000
	0 to 1	4"	0.2	0.02	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K1	00000
	0 to 2	4"	0.25	0.05	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K2	00000
	0 to 3	4"	1	0.1	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K14	00000
	0 to 4	4"	1	0.1	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K3	00000
	0 to 5	4"	1	0.1	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K15	00000
	0 to 6	4"	1	0.2	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K19	00000
	0 to 8	4"	2	0.2	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K4	00000
	0 to 10	4"	2	0.2	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K16	00000
	0 to 15	4"	5	0.5	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K5	00000


	0 to 20	4"	5	0.5	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K17	00000
	0 to 25	4"	5	0.5	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K25	00000
	0 to 30	4"	10	1	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K6	00000
	0 to 40	4"	5	1	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K27	00000
	0 to 50	4"	10	1	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K7	00000
	0 to 80	4"	20	2	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K8	00000
	0 to 100	4"	20	2	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K9	00000
	0 to 150	4"	50	5	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K18	00000


	1/8 NPT Female Threaded Pipe Connection with Calibration Certificate Traceable to NIST



			0 to 0.25	4"	0.05	0.005	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±4	4021K712	000000


			0 to 0.5	4"	0.1	0.01	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±3%	4021K711	000000
			0 to 1	4"	0.2	0.02	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K714	000000
			0 to 2	4"	0.25	0.05	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K715	000000
			0 to 3	4"	1	0.1	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K716	000000
			0 to 4	4"	1	0.1	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K717	000000
			0 to 5	4"	1	0.1	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K718	000000
			0 to 6	4"	1	0.2	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K719	000000
			0 to 8	4"	2	0.2	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K721	000000
			0 to 10	4"	2	0.2	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K722	000000
			0 to 15	4"	5	0.5	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K723	000000


			0 to 20	4"	5	0.5	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K724	000000
			0 to 25	4"	5	0.5	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K725	000000
			0 to 30	4"	10	1	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K726	000000
			0 to 40	4"	5	1	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K727	000000
			0 to 50	4"	10	1	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K728	000000
			0 to 80	4"	20	2	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K729	000000
			0 to 100	4"	20	2	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K731	000000
			0 to 150	4"	50	5	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2%	4021K732	000000

Accessories for Differential Pressure Gauges

Accessory and Air Filter Kits


Accessory Kit	Air Filter Kit

Two Vent Valves—Service these gauges without removing them using air filter kits. Kits include two vent valves for releasing air.

Includes		Each
9-ft. Lg. × 3/16" ID Tubing, Carrying Case, Mounting Bracket, Two Pipe-to-Tube Adapters	4021K31	000000
Mounting Bracket, Mounting Fasteners, Two 5 ft. Lg. Aluminum Tubing, Two Pressure Tips, Two Vent Valves	4021K95	00000

Includes		Each
7 ft. Lg. PVC Tubing Two Pressure Tips	4021K94	00000

Mounting Brackets


Surface Bracket	L-Bracket	Wraparound Bracket

Surface Bracket—Surface mounting brackets allow gauges to be quickly installed on any flat surface.

L-Bracket—L mounting brackets can be carried to wherever you need to take a pressure reading. They can stand alone or be hung.

Wraparound Bracket—Wraparound mounting brackets make it easy to service tubing, and don’t require cutting a hole in the wall.

				Mounting
Bracket Type	Lg.	Wd.	Ht.	Hole Dia.	Hole Ctr.-to-Ctr. Ht.	Hole Ctr.-to-Ctr. Wd.	No. of Holes	Fasteners Included		Each
Surface	5"	5"	—	3/16"	4 3/8"	4.281"	4	No	4021K91	000000
L	2 5/8"	4 1/2"	5 5/8"	3/8"	—	—	1	No	4021K93	00000
Wraparound	5 1/2"	7 11/16"	4"	3/16"	3.562"	6 5/8"	4	No	4021K92	00000

Low-Pressure Differential Gauges with Digital Display

Measure small changes in air pressure with these hand-held gauges. They have a four-digit LCD display for easy reading of measurements. Gauges are commonly used to indicate clogged filters and to monitor fans and blowers.

Aluminum Case with Nickel-Plated Brass Connections (Kilopascals, Inches of Water)

Image of Product. Front orientation. Differential Pressure Gauges. Low-Pressure Differential Gauges with Digital Display.

	Gauges															Nylon Carrying Cases
	Pressure Range
	Pressure 1, kPa	Pressure 2, in. H₂O	Pressure Resolution, in. H₂O	Max. Pressure, psi	Environment Temp. Range, ° F	Process Temp. Range, ° F	Digit Ht.	Ht.	Wd.	Batteries Included	For Use With	Accuracy	Hazardous Location Rating		Each		Each
Male Barbed Tubes for 1/8" to 3/16" Tube IDs



		0 to 4.982	0 to 20	0.01	10	35 to 100	0 to 140	3/8"	6 1/2"	2 13/16"	Yes	Air, Natural Gas	±0.5%	NEC Class I Division 2 Groups A, B, C, D	4125K21	0000000	4125K11	000000


		0 to 49.82	0 to 200	0.1	30	35 to 100	0 to 140	3/8"	6 1/2"	2 13/16"	Yes	Air, Natural Gas	±0.5%	NEC Class I Division 2 Groups A, B, C, D	4125K23	000000	4125K11	00000


		Male Barbed Tubes for 1/8" to 3/16" Tube IDs with Calibration Certificate Traceable to NIST



				0 to 4.982	0 to 20	0.01	10	35 to 100	0 to 140	3/8"	6 1/2"	2 13/16"	Yes	Air, Natural Gas	±0.5%	NEC Class I Division 2 Groups A, B, C, D	4125K51	000000	4125K11	00000


				0 to 49.82	0 to 200	0.1	30	35 to 100	0 to 140	3/8"	6 1/2"	2 13/16"	Yes	Air, Natural Gas	±0.5%	NEC Class I Division 2 Groups A, B, C, D	4125K53	000000	4125K11	00000

Differential Pressure and Vacuum Gauges

Commonly used to indicate clogged filters, these gauges display the difference between two pressure or vacuum measurements. They are also known as compound gauges.

Aluminum Case with Aluminum Connection—Single Scale (in. of H₂O)

Image of Product. Front orientation. Differential Pressure and Vacuum Gauges. Differential Pressure and Vacuum Gauges.

	Vacuum Range, in. H₂O	Graduations, in. H₂O	Pressure Numeric Increments, in. H₂O	Dial Dia.	Pipe Size	Max. Pressure	Environment Temp. Range, ° F	Process Temp. Range, ° F	Features	Includes	For Use With	Accuracy		Each
NPT Female



	0 to 0.2 0 to 15	-0.05 to 0	0.01	0.05	4"	1/8	0.2 in. H₂O, 15 psi	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±4% Full-Scale Accuracy (Not Rated)	4021K28	000000


	0 to 0.25 0 to 15	-0.25 to 0	0.01	0.05	4"	1/8	0.25 in. H₂O, 15 psi	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±3% Full-Scale Accuracy (Not Rated)	4021K41	00000
	0 to 0.5 0 to 15	-0.5 to 0	0.02	0.1	4"	1/8	0.5 in. H₂O, 15 psi	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2% Full-Scale Accuracy (Not Rated)	4021K42	00000
	0 to 1 0 to 15	-1 to 0	0.05	0.25	4"	1/8	1 in. H₂O, 15 psi	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2% Full-Scale Accuracy (Not Rated)	4021K43	00000
	0 to 5 0 to 15	-5 to 0	0.2	1	4"	1/8	5 in. H₂O, 15 psi	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2% Full-Scale Accuracy (Not Rated)	4021K45	00000
	0 to 10 0 to 15	-10 to 0	0.5	5	4"	1/8	10 in. H₂O, 15 psi	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2% Full-Scale Accuracy (Not Rated)	4021K46	00000
	0 to 15 0 to 15	-15 to 0	1	5	4"	1/8	15 in. H₂O, 15 psi	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2% Full-Scale Accuracy (Not Rated)	4021K47	00000


	NPT Female with Calibration Certificate Traceable to NIST



			0 to 0.2 0 to 15	-0.05 to 0	0.01	0.05	4"	1/8	0.2 in. H₂O, 15 psi	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±4% Full-Scale Accuracy (Not Rated)	4021K713	000000


			0 to 0.25 0 to 15	-0.25 to 0	0.01	0.05	4"	1/8	0.25 in. H₂O, 15 psi	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±3% Full-Scale Accuracy (Not Rated)	4021K733	000000
			0 to 0.5 0 to 15	-0.5 to 0	0.02	0.1	4"	1/8	0.5 in. H₂O, 15 psi	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2% Full-Scale Accuracy (Not Rated)	4021K734	000000
			0 to 1 0 to 15	-1 to 0	0.05	0.25	4"	1/8	1 in. H₂O, 15 psi	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2% Full-Scale Accuracy (Not Rated)	4021K735	000000
			0 to 5 0 to 15	-5 to 0	0.2	1	4"	1/8	5 in. H₂O, 15 psi	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2% Full-Scale Accuracy (Not Rated)	4021K736	000000
			0 to 10 0 to 15	-10 to 0	0.5	5	4"	1/8	10 in. H₂O, 15 psi	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2% Full-Scale Accuracy (Not Rated)	4021K737	000000
			0 to 15 0 to 15	-15 to 0	1	5	4"	1/8	15 in. H₂O, 15 psi	20 to 140	20 to 140	Two Inlets and Two Outlets	Plugs for Unused Ports	Air	±2% Full-Scale Accuracy (Not Rated)	4021K738	000000

Low-Pressure Differential Gauges with Inclined Scale

Easier to read than U-tube gauges, these use an inclined scale to measure pressure or velocity in air applications. Gauges are also known as manometers.

Polycarbonate Connections (Inches of Water)

Image of Product. Front orientation. Differential Pressure Gauges. Low-Pressure Differential Gauges with Inclined Scale.

					Indicating Liquid
	Pressure, in. H₂O	Max. Pressure, psi	Max. Process Temp., ° F	Ht.	Color	Specific Gravity	Mount Type	Mounting Fasteners Included	Includes	For Use With	Accuracy		Each
Male Barbed Tubes for 1/8" Tube IDs



		0 to 3	10	140	6"	Red	0.826	Screw On	Yes	8-ft. Lg. Tubing, Indicating Liquid	Air	±3%	3974K1	000000


		0 to 7	10	140	6"	Blue	1.91	Screw On	Yes	8-ft. Lg. Tubing, Indicating Liquid	Air	±3%	3974K2	000000

Differential Pressure and Vacuum Gauges with Digital Display

Gauges have a four-digit LCD display for easy reading of measurements. Commonly used to indicate clogged filters, these gauges display the difference between two pressure or vacuum measurements. They are also known as compound gauges.

Aluminum Case with Brass Connection—(psi, kPa, in. of H₂O, in. of Hg, mbar)

Image of Product. Front orientation. Differential Pressure and Vacuum Gauges. Differential Pressure and Vacuum Gauges with Digital Display .

	Vacuum Range, in. Hg	Pressure Resolution, in. H₂O	Max. Pressure	For Tube ID	Environment Temp. Range, ° F	Process Temp. Range, ° F	Digit Ht.	Batteries Included	Features	For Use With	Accuracy		Each
Barbed Fitting Connection



	0 psi to 0.723 psi 0 psi to 10 psi 0 kPa to 4.982 kPa 0 in. H₂O to 20 in. H₂O 0 mbar to 49.82 mbar	0 to 1.471	0.01	0.723 psi; 10 psi; 4.982 kPa; 20 in. H₂O; 49.82 mbar	1/8" to 3/16"	35 to 100	0 to 140	3/8"	Yes	40-Reading Memory, Overpressure Alarm	Air	±0.5% Full-Scale Accuracy (Not Rated)	4125K41	0000000


	0 psi to 7.225 psi 0 psi to 30 psi 0 kPa to 49.82 kPa 0 in. H₂O to 200 in. H₂O 0 mbar to 498.2 mbar	0 to 14.71	0.1	7.225 psi; 30 psi; 49.82 kPa; 200 in. H₂O; 498.2 mbar	1/8" to 3/16"	35 to 100	0 to 140	3/8"	Yes	40-Reading Memory, Overpressure Alarm	Air	±0.5% Full-Scale Accuracy (Not Rated)	4125K43	000000
	0 psi to 20 psi 0 psi to 60 psi 0 kPa to 137.9 kPa 0 in. H₂O to 553 in. H₂O 0 mbar to 1,379 mbar	0 to 40.72	0.01	20 psi; 60 psi; 137.9 kPa; 553 in. H₂O; 1,379 mbar	1/8" to 3/16"	35 to 100	0 to 140	3/8"	Yes	40-Reading Memory, Overpressure Alarm	Air	±0.5% Full-Scale Accuracy (Not Rated)	4125K46	000000


	Barbed Fitting Connection with Calibration Certificate Traceable to NIST



			0 psi to 0.723 psi 0 psi to 10 psi 0 kPa to 4.982 kPa 0 in. H₂O to 20 in. H₂O 0 mbar to 49.82 mbar	0 to 1.471	0.01	0.723 psi; 10 psi; 4.982 kPa; 20 in. H₂O; 49.82 mbar	1/8" to 3/16"	35 to 100	0 to 140	3/8"	Yes	40-Reading Memory, Overpressure Alarm	Air	±0.5% Full-Scale Accuracy (Not Rated)	4125K61	000000


			0 psi to 7.225 psi 0 psi to 30 psi 0 kPa to 49.82 kPa 0 in. H₂O to 200 in. H₂O 0 mbar to 498.2 mbar	0 to 14.71	0.1	7.225 psi; 30 psi; 49.82 kPa; 200 in. H₂O; 498.2 mbar	1/8" to 3/16"	35 to 100	0 to 140	3/8"	Yes	40-Reading Memory, Overpressure Alarm	Air	±0.5% Full-Scale Accuracy (Not Rated)	4125K63	000000
			0 psi to 20 psi 0 psi to 60 psi 0 kPa to 137.9 kPa 0 in. H₂O to 553 in. H₂O 0 mbar to 1,379 mbar	0 to 40.72	0.01	20 psi; 60 psi; 137.9 kPa; 553 in. H₂O; 1,379 mbar	1/8" to 3/16"	35 to 100	0 to 140	3/8"	Yes	40-Reading Memory, Overpressure Alarm	Air	±0.5% Full-Scale Accuracy (Not Rated)	4125K66	000000

Liquids for Low-Pressure Differential Gauges with U-Tube

Refill U-tube gauges.

Concentrates—Concentrates should be diluted with distilled water prior to use.

	Specific Gravity	Temp. Range, ° F	Color		Each
Ready-to-Use Solutions



	1	0.826	-20 to 140	Red	3974K7	000000


	1	1.91	35 to 140	Blue	3974K11	000000
	16	0.826	-40 to 160	Red	4037K21	00000


	Concentrates



			1	1	35 to 140	Green	3985K71	00000


			15	1	35 to 125	Green	4037K22	00000

Differential Pressure Sensors


Style A	Style B	Style C	Style D	Style E

Use these sensors with differential pressure gauges and switches to measure the static pressure drop across air filters, cooling coils, and blowers in air-handling equipment. Install them in duct through a hole and connect to your gauge with tubing.

Style D—Style D is held in place with a magnet so you can move it for use in multiple locations.

Pressure Tubes—Sensors with pressure tubes give more accurate measurements in applications with high air flow.

Style	For Tube ID	For Tube OD	Insertion Dp.	Fitting Connection	Gender	Mount Type	Material	Features
A	1/8" to 0.1875"	—	—	Barbed	Male	Screw On	Brass	—	4077K56
B	—	1/4"	—	Compression	Female	Screw On	Brass	—	4077K55
C	1/8" to 0.1875"	—	4"	Barbed	Male	Screw On	Brass	Pressure Tubes	4077K52
D	0.1875"	—	3"	Barbed	Male	Magnetic	Brass	Pressure Tubes	4077K53
E	—	1/4"	4"	Compression	Female	Screw On	Brass	Pressure Tubes	4077K51