Piston kits for your 135, 166, and 210 Malossi cylinder kits. Replacement kit comes with piston, rings, pin, and circlips. Please specify which cylinder kit you have and whether you need on size or oversize when ordering.
Also, on some of the 210 kits pistons can be sized by a letter i.e. A, B, C, etc� This should be visible on your old cylinder and old piston, although not all kits have this.
Not legal for use in California on pollution controlled vehicles. Check local laws before installing.