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 052A50-12NA1D Piston Accumulator, 5000 PSI, 1.5 Gallon, 5.2"OD Was: Now: $2,106.10 Add To Cart The item has been added Freudenberg NOK Sealing Technologies 047AT30-4NA1D Piston Accumulator, 3000 PSI, 0.5 Gallon, 4.7"OD Was: Now: $1,348.44 Add To Cart The item has been added Freudenberg NOK Sealing Technologies 045AT20-20NA1D Piston Accumulator, 2000 PSI, 2.5 Gallon, 4.5"OD Was: Now: $1,485.72 Add To Cart The item has been added Freudenberg NOK Sealing Technologies 047AT30-8NA1D Piston Accumulator, 3000 PSI, 1 Gallon, 4.7"OD Was: Now: $1,426.64 Add To Cart The item has been added Freudenberg NOK Sealing Technologies 052A50-.5NA1D Piston Accumulator, 5000 PSI, 0.5 Pt, 5.2"OD Freudenberg NOK Sealing Technologies 052A50-2NA1D Piston Accumulator, 5000 PSI, 2 Pt, 5.2"OD Was: Now: $1,710.44 Add To Cart The item has been added Freudenberg NOK Sealing Technologies 045AT20-2NA1D Piston Accumulator, 2000 PSI, 2 Pt, 4.5"OD Was: Now: $1,206.00 Add To Cart The item has been added Freudenberg NOK Sealing Technologies 052A50-1NA1D Piston Accumulator, 5000 PSI, 1 Pt, 5.2"OD Freudenberg NOK Sealing Technologies 047AT30-20NA1D Piston Accumulator, 3000 PSI, 2.5 Gallon, 4.7"OD Was: Now: $1,662.42 Add To Cart The item has been added Freudenberg NOK Sealing Technologies 045AT20-4NA1D Piston Accumulator, 2000 PSI, 0.5 Gallon, 4.5"OD Was: Now: $1,235.32 Add To Cart The item has been added