Liquid spray gun, connector ring, liquid spraying apparatus and adapter system

A liquid spray gun connectable to a fluid reservoir through a fluid outlet, the spray gun comprising a socket geometry arranged for engagement with a co-operating connector for releasable connecting the spray gun with the fluid outlet,

• wherein the socket geometry comprises a bore having an opening on one end, an end surface surrounding the bore's opening at least partially, and a lug portion spaced apart from the end surface in an axial direction parallel to a central axis of the bore, wherein the lug portion projects from the socket geometry towards the central axis of the bore,
• wherein the lug portion has a lower surface being adapted to engage with the connector and to retain the connector in the axial direction, and
• wherein the end surface comprises a first keying geometry that is adapted to restrict rotation of the connector in at least one direction.