38 on Panzer I Ausf.B chassis Sturmpanzer I (Bison) = 150 mm heavy infantry gun on Panzer I Ausf.B chassis Flakpanzer I = 2cm Flak 38 anti-aircraft cannon on Panzer I Ausf.A chassis kleiner Panzerbefehlswagen = armoured command vehicle on Panzer I Ausf.B chassis