Semi-automatic with three fire modes: Safe, One Round Shot, and Three Round Shot. The magazine is internal and is fed through the side of the gun. The double action trigger loads the BB and fires the CO2, propelling the .20g BB at about 380 feet per second. Most of the construction is polymer but it does feature some metal internals, a metal barrel, and a metal trigger. The pistol grip is very comfortable and the top and side rails are ideal for mounting accessories like sights, lasers, and flashlights. Comes with eight prefilled CO2 3.2oz / 90G cylinders ($70 value).