This is the Traxxas 30-Tooth Steel Idler Gear and Shaft for the 1/10 Traxxas Drag Slash and other specified Traxxas models. The hardened-steel 30-tooth idler gear provides maximum durability and power transfer in Magnum transmissions. Use as a direct replacement for Magnum 272R™ transmissions or as an upgrade for standard Magnum 272™ transmissions. Includes idler shaft.