Add durability and remove excess weight with this great option part to fit all HPI Nitro 3 and Nitro MT 2 cars and trucks! Simply replace the stock, loose parts with the stiff and lightweight parts included with this set to lower the weight of your Nitro 3 or Nitro MT 2 and tighten up the drivetrain! Just one set is needed to fully outfit your car or truck - the set includes replacement front, rear and centre gearboxes. Fits all Nitro 3 and Nitro MT 2 kits!