-390 BLACK BUNA 70D O-RING

This Buna-N NBR 70A O-Ring, item H70390, is designed for buyers who need a clear specification match for industrial fluid sealing, equipment repair, pumps, valves, cylinders and general maintenance applications. The item is specified by AS568-390; 20.953 inch (532.21 mm) ID x 0.21 inch (5.33 mm) CS; 21.373 inch (542.87 mm) OD, with 21 inch nominal ID; 3/16 inch nominal CS for cross-reference against common gland and replacement dimensions. Its Buna-N nitrile (NBR) material provides 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. Common purchasing identifiers for this product include the material name, O-ring type, dimensional size, hardness and intended sealing application. Those attributes make the item easier to compare for maintenance, OEM production, MRO replacement and reseller catalog use.