Kyosho 48 Pitch Hardened Aluminum Pinion Gear. These gears are compatible with the Kyosho Lazer and Ultima series vehicles, and are a great option for a variety of 1/10 applications. Hardended aluminum pinion gears are lighter than the steel gears, so they have less rotating mass. However aluminum pinion gears do not hold up as well in conditions where a lot of grit and dirt may get between the pinion gear teeth and the spur gear. Gears are available in a variety of tooth count options to fine tune torque and top speed. Package includes one gear and one set screw.