Dash Number 451 O-Rings | McMaster-Carr

Made of Buna-N, these O-rings resist grease, hydraulic oil, and motor oil—plus mild chemicals and water. However, Buna-N is not for use with brake fluid. These O-rings are commonly used to create multidirectional seals between two parts in power transmission assemblies, hydraulic cylinders, and pneumatic cylinders. They resist compression and tearing to keep their shape over time. All have shelf life, a cure date, and a traceable lot number printed on the package.

Inch

		Fractional										Pkg.
	Dash No.	ID	OD	ID	OD	Hardness	Specs. Met	Temp. Range, ° F	Color	Pkg. Qty.		1-9	10-49	50-Up
1/4 Fractional Width (0.275" Wide)



		451	11	11 1/2	10.975"	11.525"	Durometer 70A (Medium)	ASTM D2000, SAE AS568, SAE J200	-40 to 250	Black	2	9452K445	00000	00000	00000

Oil-Resistant Buna-N Backup Rings


O-Ring Sealing Properly with Backup Ring	O-Ring Deforms Without a Backup Ring

Image of Attribute. Front orientation. CrossSection view. Contains Annotated. Oil-Resistant Buna-N Backup Rings.

Extend the life of O-rings in oily, high-pressure systems that operate at up to 2,500 psi. These backup rings support O-rings and prevent them from deforming under pressure and causing pressure loss. Made of Buna-N, these rings won’t swell when exposed to grease, petroleum fluids, and motor oil. However, they will degrade when exposed to mild or harsh chemicals. They’re often used in hydraulic, automotive, and industrial systems. All have a shelf life, cure date, and a traceable lot number printed on the bag.

										Pkg.
	For Dash No.	Thk.	ID	OD	Hardness	Temp. Range, ° F	Color	Pkg. Qty.		1-9	10-Up
0.236" Wide



		451	0.117"	11.024"	11.496"	Durometer 90A (Hard)	-30 to 250	Black	5	5288T461	000000	000000

X-Profile Oil-Resistant Buna-N O-Rings

With four points of contact for a strong seal, these X-profile O-rings are often used in dynamic applications, such as on pistons and rotating shafts. Also known as Quattro seals and X-rings, they resist rolling and twisting better than round- and square-profile O-rings. They also require less compression to seal, which reduces friction and extends their service life. These O-rings are made of Buna-N, which is resilient and tear resistant. They resist hydraulic and motor oil.

		Fractional										Pkg.
	Dash No.	ID	OD	ID	OD	Hardness	Specs. Met	Temp. Range, ° F	Color	Pkg. Qty.		1-9	10-Up
1/4 Fractional Width (0.275" Wide)



		451	11	11 1/2	10.975"	11.525"	Durometer 70A (Medium)	ASTM D2000, SAE AS568, SAE J200	-30 to 225	Black	2	90025K636	000000	000000

Ultra-Chemical-Resistant FEP-Encapsulated Viton® Fluoroelastomer O-Rings

An FEP casing protects these O-rings from moisture and harsh solvents such as acetone, methanol, and boric acid. If the casing wears away, the Viton® fluoroelastomer core will continue to ward off chemicals. These O-rings are more flexible than PTFE O-rings and resist chemicals better than standard Viton® O-rings. They’re often used as seals in centrifugal pumps and gas venting valves. All come with shelf life, a cure date, and a traceable lot number on the bag.

		Fractional										Each
	Dash No.	ID	OD	ID	OD	Hardness	Core Hardness	Specs. Met	Temp. Range, ° F	Color		1-9	10-Up
1/4 Fractional Width (0.275" Wide)



		451	11	11 1/2	10.975"	11.525"	Durometer 55D (Hard)	Durometer 75A (Medium)	ASTM D2000, ASTM D2116, SAE AS568, SAE J200	-15 to 400	Clear with Black Core	93445K711	000000	000000

Oil-Resistant Soft Buna-N O-Rings

For a better seal in low-pressure applications, such as hydraulic return lines and oil drain plugs, these O-rings are softer than standard Buna-N O-rings. They offer the same level of oil resistance and are often used with hydraulic oil and motor oil.

Inch

		Fractional										Pkg.
	Dash No.	ID	OD	ID	OD	Hardness	Specs. Met	Temp. Range, ° F	Color	Pkg. Qty.		1-9	10-Up
1/4 Fractional Width (0.275" Wide)



		451	11	11 1/2	10.975"	11.525"	Durometer 50A (Soft)	ASTM D2000, SAE AS568, SAE J200	-30 to 225	Black	2	2418T524	000000	000000

Oil-Resistant Hard Buna-N O-Rings

Harder than standard Buna-N O-rings, these 90A durometer O-rings are more durable and wear resistant. They resist petroleum and grease, so they’re often used in hydraulic and pneumatic systems. All have shelf life, cure date, and a traceable lot number printed on the bag.

Inch

		Fractional										Pkg.
	Dash No.	ID	OD	ID	OD	Hardness	Specs. Met	Temp. Range, ° F	Color	Pkg. Qty.		1-9	10-Up
1/4 Fractional Width (0.275" Wide)



		451	11	11 1/2	10.975"	11.525"	Durometer 90A (Hard)	ASTM D2000, SAE AS568, SAE J200	-30 to 250	Black	2	5308T459	000000	00000

Water- and Steam-Resistant Parker E0603 EPDM O-Rings

Trusted for their quality and consistency, these E0603 EPDM O-rings resist water, steam, and glycol-based fluids, including brake fluid. They’re often used to seal plumbing and refrigeration systems, since they won’t swell or break down in moist environments. All have a cure date and traceable lot number printed on the bag.

		Fractional										Pkg.
	Dash No.	ID	OD	ID	OD	Hardness	Specs. Met	Temp. Range, ° F	Color	Pkg. Qty.		1-9	10-49	50-Up
1/4 Fractional Width (0.275" Wide)



		451	11	11 1/2	10.975"	11.525"	Durometer 70A (Medium)	ASTM D2000, SAE AS568, SAE J200	-70 to 250	Black	1	9557K407	00000	00000	00000

High-Temperature Parker S1138 Silicone O-Rings

Use these O-rings in temperatures up to 400° F. Made of Parker S1138 silicone, they’re pure enough for food or pharmaceutical applications—they’re USP VI certified. These O-rings are also FDA compliant for direct contact with food. All come with a cure date and a traceable lot number printed on the bag.

		Fractional												Pkg.
	Dash No.	ID	OD	ID	OD	Hardness	Specs. Met	Food Industry Std.	USP Class	Temp. Range, ° F	Color	Pkg. Qty.		1-9	10-49	50-Up
1/4 Fractional Width (0.275" Wide)



		451	11	11 1/2	10.975"	11.525"	Durometer 70A (Medium)	ASTM D2000, SAE AS568, SAE J200	FDA Compliant 21 CFR 177.2600	VI	-60 to 400	Red	1	9396K392	000000	000000	000000

Low-Temperature Chemical-Resistant FEP-Encapsulated Silicone O-Rings

Seal lines and valves in HVAC systems, freezers, and other cold applications exposed to chemicals. Made with an FEP casing, these O-rings are protected against chemicals such as methanol and boric acid. They’re a step up from Viton® fluoroelastomer in chemical resistance but less robust than PTFE. Their silicone core stays compressible even in temperatures as low as -75° F. All have a shelf life, cure date, and traceable lot number printed on the bag.

Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.

		Fractional											Each
	Dash No.	ID	OD	ID	OD	Hardness	Core Hardness	Specs. Met	Food Industry Std.	Temp. Range, ° F	Color		1-9	10-Up
1/4 Fractional Width (0.275" Wide)



		451	11	11 1/2	10.975"	11.525"	Durometer 55D (Hard)	Durometer 70A (Medium)	ASTM D2000, SAE AS568, SAE J200	FDA Compliant 21 CFR 177.1550, FDA Compliant 21 CFR 177.2600	-75 to 400	Clear with Red Core	9319K416	000000	000000

Ultra-Chemical-Resistant Rigid PTFE O-Rings

Made from PTFE, these O-rings withstand extreme temperatures and harsh chemicals such as acetone, fluorinated solvents, and ethanol. They’re also rigid, which makes them more difficult to install than flexible O-rings. These O-rings are often used to seal pump shafts, mixing tanks, and other equipment that processes chemicals or pharmaceuticals. They’re also FDA compliant for direct contact with food. All have a cure date and a traceable lot number printed on the bag.

Inch

		Fractional											Pkg.
	Dash No.	ID	OD	ID	OD	Hardness	Specs. Met	Food Industry Std.	Temp. Range, ° F	Color	Pkg. Qty.		1-9	10-Up
1/4 Fractional Width (0.275" Wide)



		451	11	11 1/2	10.975"	11.525"	Durometer 55D (Hard)	SAE AS568	FDA Compliant 21 CFR 177.1550	-300 to 500	White	1	9559K83	000000	000000

Water- and Steam-Resistant EPDM O-Rings

Made of EPDM, these O-rings have excellent resistance to water, steam, and glycol-based fluids, including brake fluid. They’re often used to seal plumbing and refrigeration systems, since they won’t swell or break down in moist environments. All have shelf life, a cure date, and a traceable lot number printed on the bag.

Inch

		Fractional										Pkg.
	Dash No.	ID	OD	ID	OD	Hardness	Specs. Met	Temp. Range, ° F	Color	Pkg. Qty.		1-9	10-49	50-Up
1/4 Fractional Width (0.275" Wide)



		451	11	11 1/2	10.975"	11.525"	Durometer 70A (Medium)	ASTM D2000, SAE AS568, SAE J200	-65 to 300	Black	1	8785N173	00000	00000	00000

Chemical-Resistant Viton® Fluoroelastomer O-Rings

Made of Viton® fluoroelastomer, these O-rings combine the oil resistance of Buna-N with the heat tolerance of silicone. They also resist a variety of chemicals, including benzene, butyl alcohol, and ethylene glycol. They’re often used to seal hydraulic systems and equipment in crude oil refineries. All have shelf life, a cure date, and a traceable lot number printed on the bag.

Inch

Brown—Brown O-rings help you tell Viton® fluoroelastomer apart from other materials.

		Fractional										Pkg.
	Dash No.	ID	OD	ID	OD	Hardness	Specs. Met	Temp. Range, ° F	Choose a Color	Pkg. Qty.		1-9	10-49	50-Up
1/4 Fractional Width (0.275" Wide)



		451	11	11 1/2	10.975"	11.525"	Durometer 75A (Medium)	ASTM D2000, SAE AS568, SAE J200	0 to 400	Black, Brown	1	9464K939	000000	000000	000000

High-Temperature Soft Silicone O-Rings

Easier to compress than standard silicone O-rings, these O-rings create a better seal in enclosures, reservoirs, and other low-pressure equipment. They can withstand temperatures up to 400° F. All have shelf life, a cure date, and a traceable lot number printed on the bag.

Inch

		Fractional										Pkg.
	Dash No.	ID	OD	ID	OD	Hardness	Specs. Met	Temp. Range, ° F	Color	Pkg. Qty.		1-9	10-Up
1/4 Fractional Width (0.275" Wide)



		451	11	11 1/2	10.975"	11.525"	Durometer 50A (Soft)	ASTM D2000, SAE AS568	-85 to 400	Red	1	1173N29	000000	000000

High-Temperature Silicone O-Rings

Made of silicone, these O-rings can withstand temperatures up to 400° F or higher. They're FDA compliant for direct contact with food, so they're often used on hot food lines. They're also used to seal HVAC systems. All come with a cure date and a traceable lot number printed on the bag.

Inch

		Fractional											Pkg.
	Dash No.	ID	OD	ID	OD	Hardness	Specs. Met	Food Industry Std.	Temp. Range, ° F	Color	Pkg. Qty.		1-9	10-49	50-Up
1/4 Fractional Width (0.275" Wide)



		451	11	11 1/2	10.975"	11.525"	Durometer 70A (Medium)	ASTM D2000, SAE AS568, SAE J200	FDA Compliant 21 CFR 177.2600	-65 to 400	Red	1	9186N465	00000	00000	00000

Oil- and Abrasion-Resistant Polyurethane O-Rings

More abrasion resistant than Buna-N O-rings, these polyurethane O-rings resist mineral oil, motor oil, and ethylene glycol. They have a round profile and are suitable for a wide range of static and dynamic sealing applications. All are sized to the SAE standard AS568.

		Fractional										Pkg.
	Dash No.	ID	OD	ID	OD	Hardness	Specs. Met	Temp. Range, ° F	Color	Pkg. Qty.		1-9	10-Up
1/4 Fractional Width (0.275" Wide)



		451	11	11 1/2	10.975"	11.525"	Durometer 70A (Medium)	ASTM D2000, SAE AS568, SAE J200	-40 to 200	Black	1	9558K442	000000	000000