8-439 FLUOROELASTOMER 90 B/U RING

Item VBU90439 is a FKM Viton 90A Backup Ring built for anti-extrusion support behind O-rings in high-pressure hydraulic and pneumatic glands. The item is specified by AS568-439; 6.475 inch (164.47 mm) ID x 0.275 inch (6.99 mm) CS; 7.025 inch (178.44 mm) OD, with 6 1/2 inch nominal ID; 1/4 inch nominal CS for cross-reference against common gland and replacement dimensions. The FKM/Viton fluoroelastomer compound is selected for high-temperature service, fuels, lubricants and many chemical sealing environments. It is with a listed temperature range of -15°F (-26°C) to 400°F (204°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. As a backup ring, it works with a primary O-ring to help limit extrusion into clearance gaps under pressure. The each-unit format supports precise replacement, kitting, resale and job-specific purchasing. Key selection details include material, hardness, product type, cross-section, inside diameter, outside diameter and application. These specification details help customers and resellers compare the part by performance requirements rather than brand name alone.