8-428 FLUOROELASTOMER 90 B/U RING

Use item VBU90428 when a FKM Viton 90A Backup Ring is required for anti-extrusion support behind O-rings in high-pressure hydraulic and pneumatic glands. The item is specified by AS568-428; 4.85 inch (123.19 mm) ID x 0.275 inch (6.99 mm) CS; 5.4 inch (137.16 mm) OD, with 4 7/8 inch nominal ID; 1/4 inch nominal CS for cross-reference against common gland and replacement dimensions. The FKM/Viton fluoroelastomer construction supports 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. 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.