444 Viton O-Ring 75A Durometer 7-3/4in ID 8-1/4in OD Pack of 25

In this review the 444 Viton O-ring is presented for technicians, maintenance crews, and DIYers who need a dependable seal for fuel, chemical, and high-heat applications; the single biggest reason to buy is its material performance - made from fluorocarbon Viton it resists fuels, aromatic and aliphatic hydrocarbons, ozone and weathering up to 400 degrees F while maintaining shape and leak resistance. The pack of 25 provides value for repeated repairs or projects where consistent size and hardness matter, and customers who need a certified standard fit will appreciate that this O-ring follows the AS568A sizing convention.

Key Features

• Viton construction: Provides strong resistance to fuels, silicone oil, chlorinated hydrocarbons and many solvents, reducing seal failures in chemical environments.
• Wide temperature range: Rated from -15 degrees F to 400 degrees F so it can be used in systems exposed to heat or cold without rapid degradation.
• 75A durometer: The medium-hard shore durometer offers a balance of compression resistance and elasticity for reliable sealing under pressure.
• Round cross-section: A classic O-ring profile that creates a tight seal between overlapping cylindrical surfaces and is simple to install or replace.
• Pack quantity: Supplied as a pack of 25 which lowers per-unit cost and keeps spare parts on hand for routine maintenance.

Who It's For

These O-rings suit industrial maintenance staff, hydraulics and pneumatics technicians, and hobbyists who work with fuel systems, vacuum equipment, or heat-exposed seals; the chemical compatibility and temperature tolerance make them a practical choice for non-flammable hydraulic fuels, aromatic and aliphatic hydrocarbons, and high-vacuum setups. The standardized sizing also helps anyone replacing common factory seals like bottle or barrel seals that accept AS568A sizes.

Those who should look elsewhere include users needing compatibility with glycol-based brake fluids, strong alkalis, ammonia gas, or super-heated steam, since Viton is vulnerable to those fluids. For applications requiring extreme low-temperature flexibility below -15 degrees F or specific approvals for food or potable water, select a material rated for those conditions.

Pros & Cons

Pros

• Excellent chemical and fuel resistance for a wide range of service environments.
• Maintains integrity across a broad temperature span, up to 400 degrees F.
• Consistent 75A hardness gives good durability and leak resistance in routine service.
• Pack of 25 provides good value for repairs and replacements.

Cons

• Not compatible with glycol-based brake fluids, strong alkalis, amines, or super-heated steam.
• 75A hardness may be firmer than desired for some ultra-low pressure or delicate sealing surfaces.

Specifications

Our Verdict

The 444 Viton O-ring is a practical, cost-effective choice for anyone needing a reliable seal against fuels, many solvents and heat. Its 75A hardness and AS568A sizing make it a durable replacement part for industrial and maintenance uses, and the 25-pack offers ready spares for ongoing service; avoid it where glycol-based fluids or strong alkalis are present.

Frequently Asked Questions

Can these O-rings be used with gasoline and aromatic fuels?
Yes, Viton is compatible with fuels and aromatic hydrocarbons, making these suitable for many fuel system seals.

Will the 75A hardness affect sealing in low-pressure applications?
The 75A durometer is firmer than softer elastomers and may be less forgiving in very low-pressure or delicate interfaces; evaluate fit and compression for sensitive seals.

Do these O-rings meet a standard size system?
Yes, the sizing aligns with the AS568A standard, which helps ensure compatibility with common OEM seals.