The MP5SD3 is the integrally suppressed variant of the MP5 with a folding stock, fitted with a unique integral suppressor that bleeds off propellant gas through 30 ports in the barrel before the bullet exits, subsonic without requiring special ammunition. The SD designation comes from the German Schalldampfer, meaning sound suppressor. Type: Submachine Gun Action: Semi/Full-Auto Caliber: 9mm Capacity: 30 Year introduced: 1974, Germany Weight: 134.4 oz Overall length: 22.2" Status: Active Military use: Yes Intended use: military, law_enforcement, special_operations