A pretty unique accessory is made by the Czech company S8M Model in the shape of a 1/72 resin Walter HWK 109-509 rocket engine. A rather large bag contains three parts.
The card shows some instructions. It reports that the -509A (single combustion chamber) can be used in Me 163A (wrong), Me 163B, J8M1 Susuj (sic), and Ba 349A Natter. It says the -509C (with cruise combustion chamber) can used in Me 163C, Me 163D, Me 263/Ju 248 and DFS 346. Although the engine designations are different in many books, recent research indicates that this engine was called -509B, with only 10 made. The only know application is the so called 'Me 163C-0' prototypes, which were Me 163B's with a rear fuselage modification (and possibly other modifications). The Me 163D, Me 263/Ju 248 had a different Walter engine installed, with rearranged component layout. Do some research before you install an engine in those models. The best place to start is the Walter HWK 109-509 Site by Shamus Reddin.
