*2103-245 PTFE S/T BUP FDA

This PTFE 55D Backup Ring, item TST245, is designed for buyers who need a clear specification match for anti-extrusion support behind O-rings in high-pressure hydraulic and pneumatic glands. The item is specified by AS568-245; 4.359 inch (110.72 mm) ID x 0.139 inch (3.53 mm) CS; 4.637 inch (117.78 mm) OD, with 4 3/8 inch nominal ID; 1/8 inch nominal CS for cross-reference against common gland and replacement dimensions. Its PTFE material provides chemical resistance, low friction and low surface energy in demanding static sealing applications. It is with a listed temperature range of -65°F (-53.9°C) to 500°F (260°C), which can help narrow material selection for heat, cold or process exposure. The white 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. 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.