Buna-N O-Rings | McMaster-Carr

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	Hardness Hardness

Durometer 50A

Durometer 60A

	Hardness Rating Hardness Rating

	Color Color

	Black		White
	Brown		Blue
	Gray		Green
	Gold

	For Use With For Use With

	Fractional Width Fractional Width

	Fractional ID Fractional ID

	Fractional OD Fractional OD

	Maximum Temperature Maximum Temperature

	Minimum Temperature Minimum Temperature

-99° to -50° F

-49° to 0° F

	Specifications Met Specifications Met

	RoHS (Restriction of Hazardous Substances) RoHS (Restriction of Hazardous Substances)

RoHS Compliant

RoHS Compliant with
Exemptions

	REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) REACH (Registration, Evaluation, Authorization and Restriction of Chemicals)

REACH Compliant

	DFARS (Defense Acquisition Regulations Supplement) DFARS (Defense Acquisition Regulations Supplement)

DFARS Specialty Metals
COTS-Exempt

	Length Length

	Thickness Thickness

View catalog pages (30)

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4,818 Products

About O-Rings

Oil-Resistant Buna-N O-Rings

Made of Buna-N, these O-rings resist grease, hydraulic oil, and motor oil—plus mild chemicals and water.

Oil-Resistant Soft Buna-N O-Rings

Softer than standard Buna-N O-rings for a better seal in low-pressure applications.

Oil-Resistant Hard Buna-N O-Rings

These hard O-rings offer better wear resistance than standard Buna-N O-rings.

Made-to-Order Oil-Resistant Buna-N O-Rings

When you need an O-ring that’s not an industry standard size, we can make one to fit your requirements. These resist grease, hydraulic oils, and motor oil.

Oil-Resistant Hard Buna-N O-Rings for Tube
Fittings with Straight-Thread Connection

Also known as Boss O-rings, these hard O-rings are for use in tube fittings with a straight-thread connection.

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

With flat edges on all four sides, square-profile O-rings cover more surface than round-profile O-rings for a better seal in static applications, such as hose, pipe, and faucet connections.

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

Also known as Quattro Seals and X-rings, these X-profile O-rings have four points of contact for a better seal in dynamic applications than round-profile O-rings. They also require less compression to make a seal, so they offer a longer service life.

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

These O-rings have eight points of contact for a better seal in dynamic applications than X-profile O-rings, plus they have eight grooves that hold lubricant to reduce friction and wear for a longer service life.

Oil-Resistant Mil. Spec. Buna-N O-Rings

Choose these O-rings for their adherence to strict military standards for material and construction.

Oil-Resistant Food Industry Buna-N O-Rings

These Buna-N O-rings are made of FDA-listed material for use with food and beverage.

Oil-Resistant Clean Room Buna-N O-Rings

These Buna-N O-rings are made and bagged in an ISO Class 7 (Fed. Std. 10,000) clean room.

Oil-Resistant Metal-Detectable Buna-N O-Rings

If these O-rings deteriorate, they can be picked up by metal detection systems.

Oil-Resistant Buna-N Backup Rings

Made of Buna-N, these backup rings resist grease, petroleum fluids, and motor oil.

Oil-Resistant O-Ring Cord Stock

Oil-Resistant Buna-N O-Ring Cord Stock

Oil-Resistant Soft Buna-N O-Ring Cord Stock

This cord stock is softer and creates a better seal in low-pressure applications than standard Buna-N cord stock.

Oil-Resistant Hard Buna-N O-Ring Cord Stock

Harder than standard Buna-N cord stock for better wear resistance.

Square-Profile Oil-Resistant Buna-N O-Ring Cord Stock

This square-profile cord stock has flat edges on all four sides, which creates a better seal than round profile in static applications, such as hose, pipe, and faucet connections.

X-Profile Oil-Resistant Buna-N O-Ring Cord Stock

The X shape of this cord stock provides four points of contact for a better seal in dynamic applications than round profile. It also requires less compression to make a seal, so it offers a longer service life.

Oil-Resistant Food Industry Buna-N O-Ring Cord Stock

Made of FDA-listed material for use with food and beverage, this cord stock resists animal and vegetable oils, citric acid, sodium bicarbonate, and grease.

O-Ring Assortments

Oil-Resistant Buna-N O-Ring Assortments

All of the O-rings in these assortments are made of Buna-N. They resist animal, vegetable, and motor oils.

Oil-Resistant Soft Buna-N O-Ring Assortments

Softer than standard Buna-N O-rings for a better seal in low-pressure applications.

Oil-Resistant Hard Buna-N O-Ring Assortments
for Tube Fittings with Straight-Thread Connection

Also known as Boss O-rings, these hard O-rings are for use in tube fittings with a straight-thread connection.

Oil-Resistant Hard Buna-N O-Ring Assortments

These O-rings are harder than standard Buna-N O-rings for better resistance to wear.

Square-Profile Oil-Resistant
Buna-N O-Ring Assortments

These O-rings have a square profile with flat edges on all four sides. They cover more surface than round-profile O-rings for a better seal in static applications, such as hose, pipe, and faucet connections.

X-Profile Oil-Resistant Buna-N O-Ring Assortments

Oil- and Chemical-Resistant O-Ring Assortments

These assortments contain a mix of Buna-N O-rings that resist oil and Viton® fluoroelastomer O-rings that resist boric acid, fuels, and transmission fluid.

O-Ring Bonding Kits

These kits include everything you need to make your own Buna-N, Viton® fluoroelastomer, or EPDM O-rings.

Reciprocating Rod and Piston Seals

O-Ring-Loaded U-Cup Seals

Also known as loaded-lip seals and PolyPaks, an O-ring secures these U-cups to the rod or piston for better sealing performance at lower pressures than unsupported U-cup seals.

High-Stability O-Ring-Loaded U-Cup Seals

Also known as Type B seals, these U-cups are wider than our other O-ring-loaded U-cup seals for better stability and fit in wider grooves.

Buna-N U-Cup Seals

These U-cup seals create less friction than O-ring-loaded U-cups, so they wear more slowly. Also known as lip seals, U-cups have a sealing lip on both the inside and outside edges, so they can be used for rod and piston sealing.

High-Speed Piston Seals

PTFE gives these seals a slippery surface that allows rod speeds more than two times faster than our other piston seals.

High-Stability High-Speed Piston Seals

A square O-ring prevents these piston seals from rocking in the groove.

Piston Seals for O-Ring Grooves

Avoid common O-ring failure in dynamic applications—the square base of these seals prevents twisting, while backup rings protect against extrusion.

Piston Cup Seals

These Buna-N seals are reinforced with cotton thread for strength.

High-Pressure Piston Seals

Rated for pressure up to 10,000 psi, these seals withstand the highest pressure of our piston seals.

Rod Seals for O-Ring Grooves

Avoid common O-ring failure in dynamic applications—the square base of these seals prevents twisting, while backup rings protect against extrusion.

High-Speed Rod Seals

The slippery PTFE surface of these seals allows rod motion up to seven times faster than our other rod seals.

High-Speed Hydraulic Cylinder Buffering Seals

PTFE gives these seals a slippery surface that facilitates rod speeds over seven times faster than our other buffering seals. They're rated for pressure up to 5,000 psi.

Air-Powered Cylinder Cushioning Seals

For use in air-powered cylinders, these seals prevent the piston from slamming against the cylinder body to minimize wear and noise.

Rod-Sealing Wipers

A two-lip design means that these wipers also function as a rod seal.

High-Speed Rod Wipers

Made from MDS-filled PTFE for a slippery surface, these wipers allow rods to move three times faster than other rod wipers.

Rotary Shaft Seals

Bore-Sealing Spring-Loaded
Rotary Shaft Seals with Wiper Lip

Ribbed Buna-N over steel creates a tight seal with the bore, even when mating with a rough surface or in a split housing.

Spring-Loaded Rotary Shaft Seals with Wiper Lip

These seals have a metal case that creates a tight seal when mating with smooth surfaces.

Spring-Loaded Rotary Shaft Seals

Also known as oil seals, use these to retain oil on rotating shafts in motors, pumps, bearings, and gearboxes. A spring secures the lip against the shaft, preventing messy leaks. Press-fit seals into the bore around the shaft.

Spring-Loaded Rotary Shaft Seals for Misaligned Shafts

Designed with an extended lip, these seals have the flexibility to accommodate shaft misalignment up to 0.125". They're also known as clipper seals.

Rotary Shaft Seals for Grease

Also known as grease seals, these are designed to retain thick lubricant at low pressure. They have a light grip on the shaft that creates less friction than spring-loaded seals.

High-Speed Rotary Shaft Seals

A slippery PTFE surface allows these seals to function at speeds at least 25% faster than other rotary shaft seals.

Split Rotary Shaft Seals

Swap out old seals without disassembling components—these seals come split for easy installation. They're also known as clipper seals.

Shaft-Mounted Rotary Seals

Made from Buna-N for excellent resistance to oil and grease.

Mechanical Shaft Seals

Commonly used in mixing and grinding equipment, conveyors, and construction machinery, these two-part seals withstand exposure to abrasive material.