Hatsan Model 135 Vortex Gas Piston Quiet Energy Break Barrel Air Rifle Single shot break barrel action. QuietEnergy fully shrouded barrel and Integrated Sound Moderator - Approximately 50% Quieter. Quattro Trigger is a 2-Stage fully adjustable match trigger system. SAS Shock Absorber System significantly reduces vibration. High quality and genuine Turkish walnut stock-hunting style, ergonomic and stylish design and montecarlo cheekpiece.