I now have a batch of three of these early war Stug III's, two Ausf B and this experimental "O" Series. That is a nice number for "What a Tanker!" (see below):
A little "kookier" than its Stug III Ausf A and Ausf B cousins but it is a very nice fast-build (with incredibly accurate parts) and is a winner in my 'tired old modelling' eyes.
PS: Others have done this a lot better (see link below):