8-148 BLACK FKM 90D BACK-UP RING

APG stocks the VBU90148, an AS568-148 black Viton® (FKM) 90 Shore A Back-Up Ring built to an inside diameter of 2.737 in (69.52 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 2.943 in (74.75 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

The compound resists aggressive chemicals, aromatic hydrocarbons, and many acids. That behavior comes from the compound itself: Viton® (FKM) is widely chosen for very low compression set at elevated temperature and outstanding high-temperature capability. Continuous operating temperature is published at -15°F (-26.1°C) to 400°F (204.4°C).

Maintenance and OEM teams specify it across aerospace, chemical processing, and oil and gas.

Order part number VBU90148, sold individually. Nominal inside diameter is listed as 2 3/4 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.