ISO 3601 D0425 Buna-N Nitrile (90A) Metric O-Ring, 90A Durometer, 42.5mm ID x 5.3mm CS (1.673" x 0.209", 53.1mm OD) - Precision-Molded Replacement Sealing Ring for Pumps, Valves & Fittings

Chasing a leak or a slow drip and need the exact metric 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 ISO 3601 D0425 o-ring, a standard metric sealing size measuring 42.5mm inside diameter by 5.3mm cross-section (1.673" ID x 0.209" CS, 53.1mm outer diameter), molded in 90A Buna-N Nitrile rubber.

Full Compatibility: ISO 3601 D0425 is an international-standard o-ring size used across pumps, valves, filters, fittings and machinery worldwide. If your application calls for a 42.5mm x 5.3mm 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.
Pro Tip: Apply Aqua Flex lubricant before installation to ease seating and extend seal life.

We are an American family-owned and operated small business committed to high-quality replacement parts and honest fitment information.