Description Accessories Description Freudenberg Sealing Technologies (formerly Tobul) backup ring is a ring of hard, extrusion resistant material such as high nitrile, nylon, Hytrel, or PTFE. A back-up ring is designed to fit between the O-ring and the extrusion gap and prevent the extrusion of the O-ring. State of California Proposition 65 WARNINGCancer and Reproductive Harm - www.P65Warnings.ca.gov. Literature & Docs Accessories Freudenberg NOK Sealing Technologies 140A30-400AJ1K Piston Accumulator, 3000 PSI, 50 Gallon, 14"OD (Non-Code) Freudenberg NOK Sealing Technologies 140A30-560AJ1K Piston Accumulator, 3000 PSI, 70 Gallon, 14"OD (Non-Code) Freudenberg NOK Sealing Technologies 140A30-640AJ1K Piston Accumulator, 3000 PSI, 80 Gallon, 14"OD (Non-Code) Freudenberg NOK Sealing Technologies 140A30-120AJ1K Piston Accumulator, 3000 PSI, 15 Gallon, 14"OD (Non-Code) Freudenberg NOK Sealing Technologies 140A30-240AJ1K Piston Accumulator, 3000 PSI, 30 Gallon, 14"OD (Non-Code) Freudenberg NOK Sealing Technologies 140A30-140AJ1K Piston Accumulator, 3000 PSI, 17.5 Gallon, 14"OD (Non-Code) Freudenberg NOK Sealing Technologies 140A30-160AJ1K Piston Accumulator, 3000 PSI, 20 Gallon, 14"OD (Non-Code) Freudenberg NOK Sealing Technologies 140A30-800AJ1K Piston Accumulator, 3000 PSI, 100 Gallon, 14"OD (Non-Code) Freudenberg NOK Sealing Technologies 140A30-480AJ1K Piston Accumulator, 3000 PSI, 60 Gallon, 14"OD (Non-Code) Freudenberg NOK Sealing Technologies 140A30-200AJ1K Piston Accumulator, 3000 PSI, 25 Gallon, 14"OD (Non-Code)