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 032A50-4NA19 Piston Accumulator, 5000 PSI, 0.5 Gallon, 3.2"OD Freudenberg NOK Sealing Technologies 040A100-2NJ14 Piston Accumulator, 10000 PSI, 2 Pt, 4"OD Was: Now: $1,603.18 Add To Cart The item has been added Freudenberg NOK Sealing Technologies 030AT30-2NA19 Piston Accumulator, 3000 PSI, 2 Pt, 3"OD Was: Now: $1,061.24 Add To Cart The item has been added Freudenberg NOK Sealing Technologies 040A100-1NJ14 Piston Accumulator, 10000 PSI, 1 Pt, 4"OD Was: Now: $1,481.24 Add To Cart The item has been added Freudenberg NOK Sealing Technologies 040A100-.5NJ14 Piston Accumulator, 10000 PSI, 0.5 Pt, 4"OD Was: Now: $1,431.84 Add To Cart The item has been added Freudenberg NOK Sealing Technologies 032A50-2NA19 Piston Accumulator, 5000 PSI, 2 Pt, 3.2"OD Was: Now: $1,128.76 Add To Cart The item has been added Freudenberg NOK Sealing Technologies 032A50-1NA19 Piston Accumulator, 5000 PSI, 1 Pt, 3.2"OD Was: Now: $1,084.96 Add To Cart The item has been added Freudenberg NOK Sealing Technologies 030AT30-.5NA19 Piston Accumulator, 3000 PSI, 0.5 Pt, 3"OD Was: Now: $1,018.70 Add To Cart The item has been added Freudenberg NOK Sealing Technologies 030AT30-1NA19 Piston Accumulator, 3000 PSI, 1 Pt, 3"OD Was: Now: $1,031.72 Add To Cart The item has been added