In 1942, U.S. Army tactical philosophy called for the use of specialized “tank destroyers,” for engaging enemy tanks. The required characteristics of a tank destroyer were a powerful gun and a high maximum speed, even if these characteristics would have been met at the expense of reduced armor protection for the crew. The M18 “Hellcat” was the fastest full-tracked, armored fighting vehicle of World War II, capable of reaching speeds up to 55-mph. It mounted a high velocity 76-mm gun capable of penetrating armor of up to 100-mm in thickness. Additionally, it had an open turret, which gave the vehicle commander a full field of vision but offered no overhead protection. The driver sat at the left front of the hull and the co-driver at the front right. The remaining three crew members were stationed in the turret: a gunner, a loader and the vehicle commander, who also operated the Browning M2 .50 cal. machine gun. M18 “Hellcats” were successfully deployed in the European Theatre from late 1943 through 1945. Over 2,500 M18s were built by Buick between 1943 and 1944.