German Sprocket wheels had the outer, teethed, ring replaceable and the new sets from T-Rex represent these disassembled wheels plus some idlers as well.
All have been 3D printed.
There are different sets for vehicles and kits as follows:
#35031 Panther Disassembled Sprocket Set A
#35032 Panther Disassembled Sprocket Set B for all brands
#35033-1/2 PzKpfw III Disassembled Sprocket Set A for DML and TAMIYA
#35034 PzKpfw III Disassembled Sprocket Set B
#35035 PzKpfw III Disassembled Idler for all brands
#35036 PzKpfw IV Disassembled Sprocket Set A Late Version for all brands
#35037 PzKpfw IV Disassembled Sprocket Set B for all brands
#35039 PzKpfw IV Disassembled Idler Casted Version for all brands
#35040 PzKpfw IV Disassembled Idler Welded Version for all brands