This is an injection-plastic military vehicle model kit.
The Sturmgeschutz III assault gun was the most-produced German armored fighting vehicle of WWII. Originally designed as a mobile light infantry support gun, it was also widely used as a tank destroyer.
Trumpeter's StuG III kit depicts the Ausf. C/D model, with short 75mm cannon and different features on the superstructure. The tracks are provided as flexible belts that can be glued. Decals are included for what appears to be two vehicles, although only one version is described in the instructions.