1mm Rear Brake Shim.  This brake shim is for non-reservoir style braking systems to shim the brake pad closer to the rotor and take up the displacement of the pad when it starts to wear.  Shims are not required for reservoir style brakes since they are self adjusting.

This brake pad is for the EVO 1 caliper which is commonly used on the Elite, Quattro, older cadets and it is a generic caliper used on other karts.