This is a Hot Racing Aluminum Speed Run Gear Cover and Rear Chassis Brace for the Traxxas 4 Tec II 4WD.
Length: 3.2" (82.5mm)
Width: 2.2" (55.5mm)
Height: 1.1" (27.8mm)
Maximum Spur Gear Size: 70T (48P)
Maximum Pinion Gear Size: 43T (48P)
1x Speed Run Gear Cover
Both maximum sized gears cannot be installed at the same time.