AS568-109 Buna-N Nitrile (90A) O-Ring, 90A Durometer, 5/16" ID x 3/32" CS (0.299" x 0.103" Actual, 0.505" OD) - Precision-Molded Replacement Sealing Ring for Pumps, Valves, Filters, Gearboxes & Hydraulics

Chasing a leak or a slow drip and need the exact o-ring size to seal it for good? A worn or wrong-size o-ring lets fluid weep past the joint, drops pressure, and can damage the equipment around it.

This Beaver Island Parts Company replacement o-ring is a single AS568-109 o-ring, a universal industry-standard size. Its nominal size is 5/16" inside diameter by 3/32" cross-section; the actual measured dimensions are 0.299" ID by 0.103" CS, held to a tolerance of ±0.005" on the ID and ±0.003" on the CS, for a 0.505" outer diameter. It is molded in 90A Buna-N Nitrile rubber and is a drop-in replacement for any standard dash-109 o-ring.

Full Compatibility: AS568-109 is a standard o-ring dash size used across pumps, filters, valves, gearboxes, hydraulic fittings, plumbing and countless machines. If your application calls for a 0.299" ID x 0.103" CS o-ring, this is the size.
Installation Note: Clean the groove, inspect the sealing surface, seat the new o-ring without twisting it, and lubricate before assembly. No special tools are required for most o-ring changes.
Pro Tip: Apply Aqua Flex lubricant to the o-ring before installation to ease seating and extend seal life.

We are an American family-owned and operated small business committed to providing high-quality replacement parts and straightforward, honest fitment information so you can fix it once and get back to work.