Wilwood caliper piston seal square ring kit, 4-piston front (1.38")

Replacement square rings for Wilwood caliper piston seals. As the name implies, these have a square cross section so you can't use generic o-rings. Kit includes enough for one Wilwood caliper with four 1.38" pistons. In the kits we sell, that's: - Dynapro front - Powerlite front (not rear) - Dynalite front (no longer used in FM brake kits)