Mr O-Ring 221 EPDM O-Ring 70A Durometer 1-7/16 in ID Pack of 100

In this review the Mr O-Ring 221 EPDM o-ring pack is examined for workshop and maintenance use; it is aimed at technicians, hobbyists and equipment owners who need a reliable, weather-resistant seal in bulk. The single biggest reason to buy is the combination of a common AS568-equivalent size and EPDM compound properties - the 70A durometer gives a balance of flexibility and durability while the pack of 100 reduces downtime for routine replacement. The review focuses on real-world sealing, temperature tolerance and chemical compatibility.

Key Features

• 221 EPDM formulation: provides strong resistance to ozone, sunlight and weathering so seals last outdoors and in exposed installations.
• 70A Durometer: offers a balanced hardness that retains flexibility at low temperatures while resisting extrusion in static and dynamic seals.
• Pack of 100: a large quantity reduces reordering frequency and is convenient for shops and preventive maintenance programs.
• Wide temperature range: rated from -55C to 125C so the o-ring works across cold storage, engine bays and many industrial environments.
• Chemical compatibility: performs well with water, alcohols, brake fluid, dilute acids and alkalies and some hydraulic fluids for broad application coverage.
• AS568 size equivalent: nominal and actual dimensions match common sizing for straightforward replacement and interchangeability.

Who It's For

This product is best for maintenance teams, small repair shops and DIY technicians who need a consistent supply of a common EPDM o-ring size for plumbing, HVAC, automotive non-fuel systems and general sealing tasks. The bulk pack is useful where multiple replacements are expected or where stocking spare parts prevents downtime.

Those who need resistance to petroleum-based oils, aggressive hydrocarbons or certain silicone fluids should look elsewhere, because EPDM is not recommended for many fuels and some nonpolar solvents. If you need a softer or much harder durometer, a different compound or specific material certification may be required.

Pros & Cons

Pros

• Excellent resistance to ozone, sunlight and weathering for outdoor and exposed seals.
• Good low temperature flexibility and a practical 70A hardness for many sealing tasks.
• Large 100-count pack is cost-effective for workshops and routine maintenance.

Cons

• EPDM is not suitable for many petroleum-based fluids, so it is not universal for all automotive seals.

Specifications

Our Verdict

The Mr O-Ring 221 EPDM 70A pack is a practical choice for anyone needing a dependable, weather-resistant o-ring in a common size and in quantity. It represents good value for preventive maintenance and general sealing where EPDM compatibility is acceptable, but avoid it for petroleum-based fluid applications.

Frequently Asked Questions

Are these o-rings AS568-compliant?
They match AS568 nominal sizing and actual dimensions for direct replacement in most applications.

Will these work with engine oil or fuel?
No, EPDM is generally not compatible with petroleum-based oils and fuels; choose a different material for those fluids.

Can they handle steam and high temperature briefly?
Yes, EPDM has steam resistance up to about 204.4C (400F) for short exposures, while continuous service is rated to 125C (257F).