Crosman worked with Hans and Ray Apelles, two world-class airgunners, to develop the new Challenger Dual Fuel competition air rifle. Challenger Competition Air Rifle Approved by the Civilian Marksmanship Program (CMP) for 3-position air rifle Sporter Class competition High-pressure air (2,000 psi) or CO2 (Dual Fuel) Single-shot Bolt-action (ambidextrous & straight pull) 2-stage, match-grade, adjustable trigger Lothar Walther barrel Adjustable cheekpiece Adjustable buttpad stretches rifle's length from 38.75" to 41.75" 12.5" is the shortest length of pull available Hooded front sight with aperture inserts Fully adjustable diopter rear sight 11mm scope rail Adjustable striker spring to fine-tune velocity Fully free-floated Lothar Walther barrel Black synthetic stock Approx. 70 shots per tank at 530 fps Ideal for 3-position competition Air reservoir has a male Foster fitting (you need to buy an adapter if you plan to use CO2) Owner's manual incorrectly states a degasser is included. It is not.