The ADEN Mk 5 became the basis for the planned ADEN 25, which was to be a somewhat larger weapon (length: 90 inches (2,290 mm), weight: 203 pounds (92.1 kg)) firing the new range of NATO 25 mm ammunition (as in the American GAU-12 Equalizer) at a much higher muzzle velocity of 3,445 feet per second (1,050 m/s).