Developed concurrently with the DEFENDER silencer for the H'K UMP .45 ACP submachinegun, Advanced Armament Corp.'s ECLIPSE and TACTICAL are efficient tools for eliminating the sound and flash of .45 ACP semi-automatic pistols. Introducing 5cc's of water to the rear of the ECLIPSE and TACTICAL enable them to deliver an unprecedented 35+dB reduction for approximately three magazines (20 to 25 rounds) of use. The ECLIPSE generates sufficient back-pressure to reliably cycle the 1911 and Sig P-220, while the TACTICAL is engineered to function with the Heckler ' Koch Mk-23, USP Tactical and Glock 21 .45 ACP, without the added complexity and expense of recoil enhancing equipment.