Mr O-Ring 268 Viton O-Ring 90A Durometer, 8-1/2in ID Pack of 10

In this review the focus is on a workhorse sealing component: the Mr O-Ring 268 Viton O-Ring in a pack of 10. The bottom line is that this set is best for technicians and maintenance shops that need a reliable, high-temperature resilient seal in common AS568 sizes; the single biggest reason to buy is the combination of a 90A durometer Viton compound and accurate nominal plus actual dimensions that make replacements fit without guesswork. The review examines performance, sizing, temperature tolerance and typical applications to help decide if this is the right o-ring for a given task.

Key Features

• Material: Viton FKM offers excellent resistance to fuels, oils, ozone and many chemicals, providing durable sealing in harsh environments.
• Hardness: 90A durometer gives a firm seal suitable for static and low-dynamic applications where compression set resistance matters.
• Size accuracy: Nominal 8-1/2in ID with actual measured dimensions (8.484in ID, 8.762in OD, 0.139in CS) reduces time spent adjusting for fit when replacing AS568 o-rings.
• Temperature range: Rated from -26C (-15F) to 232C (450F), making these o-rings useful across a wide thermal span from cold storage to high temperature systems.
• Versatile compatibility: Performs well with petroleum products, diesel, biodiesel blends, silicone oils, and many solvents, so one pack covers multiple service types.
• Pack quantity: Supplied as a pack of 10 for routine maintenance or multiple assemblies, helping shops keep spares on hand.

Who It's For

This pack is aimed at industrial maintenance technicians, HVAC and plumbing professionals, and small shops that service pumps, valves and fuel-handling equipment where a resilient fluorocarbon seal is required. The 90A hardness and temperature rating make it a good match for static seals, fuel systems, and applications exposed to heat or ozone.

Those who should look elsewhere include applications demanding very soft, low-force seals or continuous dynamic rotary seals where a lower durometer or specialty elastomer is preferred. Also, if an exact non-AS568 custom size is needed, a custom-molded seal would be more appropriate than this standard size pack.

Pros & Cons

Pros

• High chemical and heat resistance from the Viton FKM compound for long service life in harsh fluids.
• Accurate actual dimensions listed alongside nominal sizes reduce fitment uncertainty during replacements.
• 90A hardness is a practical balance for many static and low-dynamic sealing tasks.
• Pack of 10 keeps spares available for routine maintenance work.

Cons

• At 90A durometer the o-ring is relatively firm and may not be ideal for soft-sealing or low-compression applications where a lower hardness is required.
• Not intended for continuous high-speed rotary shaft sealing where specialized compounds or designs are preferred.

Specifications

Brand	Mr O-Ring
Material	Viton (Fluorocarbon rubber, FKM)
Durometer	90A
Nominal dimensions	8-1/2in ID, 8-3/4in OD, 1/8in CS
Actual dimensions	8.484in ID, 8.762in OD, 0.139in CS
Temperature range	-26C (-15F) to 232C (450F)
Pack quantity	10 o-rings

Our Verdict

This pack of Mr O-Ring 268 Viton o-rings is a practical, cost-effective choice for professionals needing reliable, high-temperature resistant seals in a common AS568 size. Its measured actual dimensions and 90A hardness make it a dependable replacement option for static and many low-dynamic sealing tasks, offering good value for shops that service fuel, oil and heated systems.

Frequently Asked Questions

Can these o-rings handle fuel and oil exposure?
Yes. The Viton FKM compound tolerates petroleum products, diesel and biodiesel blends, mineral oils and many solvents listed in the product details.

Are the dimensions precise enough for direct replacement?
Yes. The listing provides both nominal and actual measured dimensions so they can be matched to AS568 size requirements for direct replacement.

Is this suitable for continuous high-speed rotary applications?
No. The 90A Viton is more suited to static and low-dynamic seals; continuous high-speed rotary seals typically need specialized designs or compounds.