The M3 Stuart is designed to counter the other European tanks if a conventional war took place, such as the Panzer III, BT-5, the Valentine, and the French FCM-36 light tanks. It's 37mm gun was formidable during that time. Until the Introduction of the Panther and the Panzer IV medium tanks made it obsolete to fight German armor. But in the Pacific and in Italy, the Fiat L6/40 and the japanese Type 97 medium tanks never had a match for the Stuart. It's chassis was also used for the light M8 SPG.