GAMO Bone Collector Bull Whisper IGT air rifle IGT gas piston (IGT=Inert Gas Technology) Breakbarrel Single-shot 11mm optics dovetail No open sights Bull Whisper noise dampener Rifled steel barrel with fluted polymer jacket All-weather synthetic green stock with black rubber inserts Dual raised cheekpieces (ambidextrous) Textured pistol grip and forearm Manual safety Smooth Action Trigger (SAT) 2-stage adjustable trigger Shock Wave Absorber (SWA) recoil pad absorbs up to 74% more recoil Includes 4x32 scope, mount, elasticized scope lens covers, hex wrench, cleaning cloth and PBA ammo Here are the benefits of the IGT over a metal mainspring: Smoother cocking Smoother shooting No spring torque No spring fatigue, even if you leave it cocked for hours Functions perfectly in cold weather Lasts longer than a metal spring. Pellets not included.