The BBX11 is a blowback .177 caliber BB gun powered by a 12 gram CO2 capsule. Both BBs and the CO2 are housed in the drop-free full size magazine. With a skeletonized trigger and hammer, the blowback action BBX11 is pure fun on the range. BBs will fly at 410 FPS. You will definitly want to pick up a spare magazine or two to keep the BBs flying. The BBX11 is powered by a single 12g non-threaded CO cartridge (purchased separately).