Kyosho W5303-09 Big Bore Shock Piston 2-Hole (2)

Kyosho W5303-09 is a genuine pair of two-hole shock pistons for Kyosho's big bore dampers. The piston is what actually creates damping: oil is forced through its holes as the shaft strokes, and the number and diameter of those holes decides how much resistance the shock produces. A two-hole piston restricts flow more than a three-hole, which gives a firmer, more packed damping feel that resists bottoming on big jump landings and keeps the chassis settled on smooth, high-speed tracks.

Piston changes work hand in hand with oil weight, and many racers prefer to change pistons rather than chase very thick or thin oils, since hole count gives a more consistent effect across temperature swings. These install as a direct-fit tuning option in Kyosho's big bore shocks, fitting the Ultima RT6, RB6, and SC along with the Lazer ZX-5 series and later SP models. Package includes two pistons, enough for one pair of shocks.