The UMP is a German sub-machine gun developed by Heckler & Koch. It has been manufactured since 1999, in three different calibers: 9mm (Parabellum), .40 (S&W), and .45 (ACP). The UMP9 and UMP40 versions are fed by a 30-round detachable fox magazine, while the UMP45 variant uses a 25-round magazine. This German sub-machine gun has a blowback operation system, which shoots from a closed bolt, a barrel length of 20 cm (8in), and an effective range of 100 m (101 yards). Loaded, the UMP 45 weighs 2,7 kg. The ejection port of the UMP is located on the right hand side. The weapon also features a fire selection switch lever (for semi-automatic, 2-round burst, fully automatic, and safe), a folding stock, and a fore handgrip, which can be attached under the barrel, which has two lugs, right behind the flash hider, for the attachment of a silencer. "UMP" is an acronym that stands for the German words "Universale Maschinenpistole", which means "Universal Machine Pistol".