Carro Armato (armored tank) was the Italian Armys designation for tanks from 1938. This would be followed by a letter and a series of numbers. The letter would be either L, M or P meaning light, medium, and heavy tank respectively. The official Italian military tank classification differed from contemporary classifications in other countries. For example the heavy P40 tank would be considered a medium tank by the US armed forces. The numbers would follow the pattern of XY where X would be the weight in tonnes and Y the year of adoption (i.e. the L640 weighs 6 tonnes and was adopted in the year 1940).