The Crosman 114 is an air rifle. It is filled with bulk co2. It used to come with a refillable tank, kinda like modern paintball tanks. You simply screwed it on, opened the valve, filled it with co2, closed the valve, took off the tank, and shot until out of air. Bryan and Assoc. currently has one listed in excellent condition, for $135. Not to burst your bubble, but I don't think they are all that rare. It shoots 22 caliber pellets. Hope this helps, Billy