3.975" (100.97MM) ID X .275" (6.99MM)

Use item H70421 when a Buna-N NBR 70A O-Ring is required for industrial fluid sealing, equipment repair, pumps, valves, cylinders and general maintenance applications. The item is specified by AS568-421; 3.975 inch (100.97 mm) ID x 0.275 inch (6.99 mm) CS; 4.525 inch (114.94 mm) OD, with 4 inch nominal ID; 1/4 inch nominal CS for cross-reference against common gland and replacement dimensions. The Buna-N nitrile (NBR) construction supports oil, grease, fuel and general hydraulic fluid resistance in common industrial equipment. It is with a listed temperature range of -40°F (-40°C) to 250°F (121°C), which can help narrow material selection for heat, cold or process exposure. The black color and round profile provide a practical visual identifier during receiving, stocking and installation. This standard industrial O-ring can be used across compatible static and dynamic sealing applications in pumps, valves, cylinders and assemblies. The each-unit format supports precise replacement, kitting, resale and job-specific purchasing. Important product identifiers include O-rings, replacement seals, fluid sealing, material compatibility and dimensional fit. It supports customer comparison, distributor cataloging and specification-based selection without relying on pricing, availability or shipping claims.