Its proper name is 15cm sIG 33 auf Fahrgestell Panzerkampfwagen II (Sf), which is a hell of a mouthful. I'm just going to keep calling it Bison.
The base model I built this up from was by Bergman, though all that's left is (most of) the hull. I replaced the running gear and gun, rebuilt the engine grills, and cobbled together a couple of crewmen from some figures by someone whose name I've forgotten.
As usual, when I've decided to do some paint chipping, I've gone completely overboard. This looks more like shrapnel damage than normal wear and tear.
Scale is 1:100 (15mm)