If you want to tear down and rebuild a two-piece four-piston STI Brembo front caliper (or the corresponding two-piston rear caliper), you'll need these special O-rings, which are specifically sized for the internal fluid passage between the caliper halves. These O-rings are made by and purchased from Brembo, specifically for Brembo calipers.

Brembo doesn't specify torque on the fasteners, but based on the fastener size, 35-40 ft-lbs should be about right.

Dime shown for scale; not included.

Fits all gold, red, or black STI Brembo two-piece front or rear calipers. That includes BRZ/FR-S/Toyota GR86 Performance Pack Brembo calipers.

Set of two O-rings, enough for two calipers.