Parbak® back-up rings are made from hard elastomers and prevent migration of O-rings into the sealing gap when subjected to high pressures.
Parbak® is a Parker standard rubber back-up ring of contoured design which improves the sealing effect and increases service life. It is intended for use in dynamic and static seal applications.

Features of Parbak® back-up rings:
• Elastic memory permits Parbak® rings to be stretched into place for assembly without preconditioning or cutting
• Continuous construction prevents damage to the O-ring seal
• Lubrication is enhanced by rubber which absorbs system fluid and does not plate out on rubbing surfaces
• For a wide temperature range from -25 °C to 200 °C
• Compatible with a wide range of fluids

Radius of the groove bottom r1 = 0.2 - 0.4 mm

Parbak® back-up ring Praedifa series is available in the following compounds:
N0300-90
V0709-90