This kit includes ALL the seals and stainless steel pistons for a complete caliper refresh. Each kit does ONE caliper, two kits are required per axle.
Lucky enough to have a 69-75 911 but your pistons are questionable? This bundle may be for you. This actually works for any ATE calipers with the contoured top pistons (not the cup style that began showing up on the scene around 1976). This has the smaller neck in the dust boot for the earlier style pistons. These bundles include the caliper 1/2 o-ring seals and a pair of our famous "set it and forget it" stainless steel pistons. You'll never have to replace your pistons again.
Fun Facts: Later the "booster circuit" came into existence with the 911 around 1976. These cars had a caliper piston that was cup shaped as they no longer needed the "knockback" pin and mechanism. The booster circuit accomplished the same job by applying 2-3 psi residual pressure on the system. The later cup style piston had much more surface area for cooling. That style piston lives on in today's modern calipers.
You may want to consider our seal kit bundle (below) for the best price available on this kit with new, lifetime stainless pistons.