Converted to heavy duty 32 pitch (bigger tooth profile) from the smaller 48 pitch stock gears, precision machined, hardened steel, with a blackened finish that improves lubricity (the capacity to reduce friction) and anti-galling (metal cracking/breaking from friction) characteristics resulting in better mating surfaces and smoother running gears. Includes an extra-hard steel pinion gear. The GEN3 Slipper Unit will handle 3S LiPo's no problem! Includes: 58 tooth hard black steel spur, 13 tooth extra-hard steel pinion, aluminum backplate, slipper pad, reducer sleeve, and cone washers. Note: Pinion gears with 11 to 15 teeth will fit using the stock mounting holes.