حلقات O-Ring HNBR 0.21" CS X 4.975" ID | AS568-351 | داش 351 | صلابة 80 (7 / عبوة)

Installed these in a hydraulic manifold that sees 275°F peaks and they've held up perfectly so far—no leaks or hardening. The 80 durometer feels just right for the pressure we're running.

The 0.21" cross-section feels properly beefy when I stretch it over the flange, and the 4.975" ID seats without any wrestling. These HNBR rings handled a 250°F oil bath for a week without losing their shape, which is exactly what I needed for the hydraulic repair.

The -40°F low-end rating gives me confidence these will hold up in our unheated warehouse during winter freezes. I've installed a set on a hydraulic cylinder and the 80 durometer feels noticeably stiffer than the standard 70—exactly what I needed for the higher pressure application.