A 3-hole specification has been added to the popular OD fluororesin shock piston. It reduces (softens) the damping in the low piston speed range, while providing firm damping even in the high piston speed range. It can be used to create shocks with characteristics that are particularly suitable for technical courses. Two blanks each of φ0.6, φ0.7, and φ0.8 are included in the set for both Tamiya TRF and Yokomo BD.