The Sturmtiger, based on the Tiger I, was armed with a short-barreled 38cm Raketenwerfer 61 L/5.4 breech-loading rocket launcher/mortar. The RW 61 launcher fired short-range (4,600 to 6,000meters). Only 18 Sturmtigers were produced, and they did not have any effect on the outcome of the war. In their limited use, Sturmtigers proved to be excellent defensive weapons but were slow and mechanically unreliable.