The TK project was realized to obtain a tankette derived from a similar British design, the Vickers Carden Loyd Mk. VI. At the outbreak of the conflict the 575 TK/TKS tankettes constituted the bulk of the Polish armored forces before the outbreak of war against Hitler's Germany. Like the entire Polish Army, the tankettes suffered heavy losses during the invasion of Poland, often being the only armored fighting vehicles available. Their very small size made them suitable for reconnaissance and infantry support, but with their light armament, consisting of a single machine gun, these vehicles had no chance against German tanks, except perhaps against Panzer Is. After the defeat they were used by the Germans, who, however, did not particularly appreciate them.