Gamo's powerful Whisper Fusion Mach 1 air rifle features Whisper technology. It is an integrated noise and muzzle blast reducer overmolded on the barrel, making this air rifle quiet. It also features the IGT Mach 1, which replaces the standard spring powerplant with an Inert Gas Cylinder. The IGT Mach 1's monster 33mm cylinder delivers more velocity and terminal penetration, not to mention smooth and consistent cocking efforts with constant power delivered to any pellet you fire. .