Back-up rings are washer-like devices that are used to prevent a seal from extruding through any gaps while under pressure. These seals are installed in the downstream side of the gland. Back-up rings are not seals themselves, but are usually used in conjunction with O-rings in high-pressure applications (over 1500 psi) for support or as spacers.
Molded of a 90A Durometer Buna-N Rubber. The 574 Style dished Cross section back-up rings provide excellent extrusion resistance. Stretched for installation, they return quickly to their original size for easy installation.
PLEASE NOTE: Sizes (Dash NO.) Corresponds to standard o-ring numbers