The M4A3 is a 9mm automatic, recoil operated, magazine-fed handgun. The working mechanism is made of steel alloy with some high-strength plastic parts, while the outer casing is machined from lightweight alloys. The entire weapon, including a full 12-round magazine, weighs no more than 0.95 kg. The M4A3 is largely ineffective at stopping most Xenomorphs and Yautja, making it somewhat of a last resort weapon.