The ULTIMATE extreme performance piston made of a 50% stronger polycarbonate resin, with embedded steel teeth specifically designed for high-speed tunes and extreme heavy tuning of 150-190 m/s.All dimensions of the piston has been reworked to fit perfectly inside ULTIMATE gearboxes and gives a smooth low friction performance.The length has been adjusted to make a perfectly even contact between the first gear and the first teeth of the piston preventing breakage and minimizing wear.With ULTIMATE Extreme performance piston you get: Increased strength. Increased durability. Low friction. Perfect fit in ULTIMATE gearbox. Perfect combinations of polycarbonate teeth and steel for impact-energy absorption and strength. Reinforcement bar gives superior structural strength to the piston-teeth. Optimal angel for first-contact between piston and gear. 50% stronger polycarbonate (then ULTIMATE high performance piston)