ICS Airsoft presents the upgrade parts for their CXP-Tomahawk that allow you to customize it to your liking. You can choose from the following parts: MT-92 Air Brake, MT-94 Variable Capacity Cup, MT-93 Variable Mass Piston, MT-95 Steel Spring Guide with Thrust Bearing, and MT-96/97 TMH Twisted Fluting Outer Barrel 20.8 inch/15 inch.