568-389 BUNA 70 SQUARE CUT RINGS

This Buna-N NBR 70A Square Ring, item SH70389, is designed for buyers who need a clear specification match for static sealing and gland designs that call for a square-cut sealing profile. The item is specified by AS568-389; 19.953 inch (506.81 mm) ID x 0.21 inch (5.33 mm) CS; 20.373 inch (517.47 mm) OD, with 20 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 square profile provide a practical visual identifier during receiving, stocking and installation. The square-cut profile can help fill rectangular glands and provide broad contact for compatible static sealing designs. 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.