The present invention relates to a spray gun cup lid comprising a lid body (360) comprising a liquid outlet (310); and a flange (371) positioned at an outer periphery of the lid body (360), the flange (371) comprising a lid connection structure (370); the lid connection structure comprising a flange tab (372) comprising a lid engagement member (374), wherein the lid engagement member (374) comprises a lid camming surface (376), wherein the lid body (360) comprises an inner lid body surface (361) and wherein the lid camming surface (376) faces generally toward the inner lid body surface (361), wherein the flange (371) comprises a flange opening (380) dividing two flange tabs (372).