412 O-Ring Viton 75A 2-7/8 in ID 3-3/8 in OD - Durable Chemical Seal

In this review the 412 O-Ring made of Viton is evaluated for routine and demanding sealing tasks; the bottom line is that it is best suited for users who need a heat- and fuel-resistant replacement O-ring with predictable hardness and size. The reviewer found the pack of five particularly useful for maintenance work where matching exact dimensions matters, and highlights the material's resistance to fuels, aromatic and aliphatic hydrocarbons, and high temperatures as the single biggest reason to buy. Its 75A durometer delivers a firm but flexible gasket that holds compression on cylindrical overlaps without squishing out too quickly.

Key Features

• Viton compound: Resists fuels, many chemicals and ozone so seals last longer in oil- and fuel-exposed installations.
• 75A durometer: Provides a balance of firmness and elasticity to maintain a reliable seal under compression and thermal cycling.
• Standard AS568A size: The 2-7/8 in ID and 3-3/8 in OD match common aerospace and equipment dimensions for easy replacement.
• Wide temperature range: Rated from -15 degrees F to 450 degrees F so it performs in cold storage and high-heat engine zones.
• Round cross-section: Designed to seal between cylindrical overlapping surfaces for predictable compression and leak resistance.

Who It's For

This product is ideal for technicians, mechanical hobbyists, and equipment maintainers who need a repeatable, chemically resistant O-ring in a standard AS568A size. The pack format suits workshops that replace seals regularly on fuel bottles, firearms components, hydraulic fittings, or vacuum systems where Viton compatibility is required.

Those who should look elsewhere include users needing compatibility with strong alkalis, ammonia gas, glycol-based brake fluids, or super-heated steam, because Viton is vulnerable to those media. If an ultra-soft seal or a different cross-section is required, choose a different material or profile.

Pros & Cons

Pros

• Excellent chemical and fuel resistance for long life in oil- and fuel-exposed applications.
• Good heat tolerance so it holds up around engines and hot process equipment.
• Correct AS568A dimensions and firm 75A hardness deliver reliable fit and leak resistance.
• Pack of five gives value for repeat maintenance or multiple installations.

Cons

• Not compatible with strong alkalis, ammonia, certain amines or glycol-based brake fluids, limiting use in some brake or chemical systems.
• 75A hardness may be too stiff for applications that require a very soft, low-compression seal.

Specifications

Material	Viton (fluorocarbon elastomer)
Durometer	75A
Inside Diameter (ID)	2-7/8 in
Outside Diameter (OD)	3-3/8 in
Cross-section / Width	1/4 in
Temperature Range	-15 degrees F to 450 degrees F
Standards	Meets AS568A size standard

Our Verdict

The 412 Viton O-ring is a practical, value-oriented choice for anyone needing a durable, heat- and fuel-resistant seal in a common AS568A size; its 75A hardness and pack of five make it especially useful for replacements on fuel bottles, firearm seals, and hydraulic fittings. It is not the right choice where alkali or glycol brake fluid resistance is required, but for typical fuel and high-temperature sealing it represents good value.

Frequently Asked Questions

Is this O-ring suitable for fuel applications?
Yes, Viton is compatible with many fuels, aromatic and aliphatic hydrocarbons, and is commonly used in fuel-handling seals.

Will this O-ring withstand high temperatures?
Yes, it is rated for use from -15 degrees F up to 450 degrees F, so it tolerates most engine and hot-process environments.

Can it be used with brake fluid or ammonia?
No, Viton is vulnerable to glycol-based brake fluids, ammonia gas, certain amines and strong alkalis, so avoid those media.