By the start of WWII the US Army had a need for light cross country and reconnaissance vehicle. Willys won the contract although later on Ford were contracted to produce the Jeep as Willys could not keep pace with demand. The Willys Jeep served with all allied forces during WWII. Introduced in 1940, the M3 37mm Anti Tank gun was the first US dedicated anti tank gun. It was adopted as the standard AT gun of the US infantry and its size allowed it to be towed by or mounted in the Willys Jeep.