The Umarex EBOS (short for Electronic Burst of Steel) is a tactical BB rifle that allows you to shoot in 1, 4, or 8 shot bursts. The high velocity 540 fps. The top- and bottom-tactical railing lets you customize your gun with any point sight, flashlight, or laser enhancements that you would like to add. The gun is powered by a single 88 g CO2 capsule. The ergonomic pistol grip and removeable fore-grip give you the ability to shoot comfortably all day long. CO2 Air Rifles