Difference between mixer shower 4 gravity fed /combi boiler?

[silver3in]

Hi,
Does anyone know if the cartridge of a gainsborough mixer shower would be different for a combi & gravity fed system? If they are different then could someone simply explain the difference in cartridge's design & functioning? Thanks.

 

[seco services]

Gainsborough what model ?

 

[silver3in]

Gainsborough Ambassador mixer

 

[seco services]

Pink combi grey gravity/pumped

 

[silver3in]

Thanks. Would you know what would happen if say I used a combi shower with a gravity fed system?