difference between Benz MB Star Compact C3 and C4

[Tomy2008]

Hello,
Sorry for my stupid question, i want to know the difference between MB Star Compact C3 and MB STAR COMPACT C4.
I notice the same description for these two items.
If i want to use on all Mercedes-Benz models for diagnosis, coding and key programming, which tool should i purchase?

[Zurick-Sokhumi]

Compact C3 is old device, COMPACT C4 is new and better, the difference is not large. Is also newest XENTRY CONNECT.
If you want to use on all Mercedes-Benz models for diagnosis, coding and programming you must purchase COMPACT C4.
For key programming you must to purchase separately special key programming device.