You must add a |reason= parameter to this Cleanup template – replace it with {{Cleanup|February 2005|reason=<Fill reason here>}}, or remove the Cleanup template.
The SiG33 appears to be the designation of the 150mm artillery gun which was placed on various chassis.
Various chassis were used - PzKpfw I, II and the 38(t).
One variant on the Panzer III chassis fitted a fixed box like structure with an almost vertical front glacis plate and was also armed with an MG34.