High-performance replacement 34mm piston seal designed for StopTech ST-40 and ST-42 brake calipers. This premium EPDM rubber seal ensures optimal hydraulic pressure retention and piston retraction, maintaining consistent braking performance and preventing fluid leaks. It is fully compatible with professional big brake kits and several OEM applications using 34mm piston diameters. Contains: 1 x StopTech 34mm Piston Seal (P/N 753.24471S). Note: One seal required per piston; for a full caliper rebuild, order based on the number of 34mm pistons present.