حلقات O من مطاط بونا-N نيترايل | AS568-928 | داش 928 | صلابة 90 (300/عبوة)

The 300-count pack is a solid deal when you're rebuilding a bunch of pneumatic fittings at once, and the -40°F rating gives me peace of mind for outdoor equipment in winter. These have a firm, dense feel that seats cleanly without squishing out of the groove.

These 90 durometer rings are noticeably stiffer than the standard ones I've used before, which made fitting them into a tight groove much easier. The package of 300 should last me through several rebuilds.

Installed these on a water pump flange that sees constant 200°F heat, and they’ve held up perfectly for two months. The 90 durometer material is stiff enough to keep a tight seal without cracking.