PN#21700  SKU#13544  4 Ways Better!. 1. LOW FRICTION! Wrinkle Band cuts friction in half. Rings slide in easily. 2. WRINKLE BAND! Can’t slip down into cylinder. 3. CAM OPERATED! Set adjustment screw just once for entire set of pistons. 4. FASTER! Insert a full set of pistons in half the time, with half the work! With a range of 3″ to 5″.