Brake pad spacers are .125" and are made from plated steel. Pack of 2.
Brake pad spacers are designed to prolong the life of brake pads and prevent damage to the caliper. If using a 3/16" (thin) rotor these spacers are mandatory. The caliper is not designed to use a 3/16" rotor, the caliper pistons will come out of the pockets, get forced sideways, and ruin the rotor and caliper if you do not use brake pad spacers.