A connector system (47, 48, 49, 50) for a medical application including: - a male single channel fluid connector designed with an inner tube for passing of fluid, and a center collar with a threaded inner side and arranged concentric with the inner tube, the center collar being defined by an outer diameter M1_od; - a female single channel fluid connector designed with a tube for passing of fluid, the tube having a threaded outer side; characterized in that the male single channel fluid connector is designed with an outer collar arranged concentric with the inner tube outside the center collar, the outer collar is defined by an inner diameter M2_id and an outer diameter M2_od and a space in-between the center collar and the outer collar defining a depth stop, wherein the space has an axial depth length M2_dl; and wherein the center collar optionally is designed to have an axial top length M1_tl extending beyond the outer collar; and wherein the female single channel fluid connector further is designed with an outer collar arranged concentric with the tube and defined by an inner diameter F1_id and an outer diameter F1_od, and a space in-between the tube and the outer collar defining a depth stop, wherein the space has an axial depth length F1_dl; and wherein the outer collar optionally is designed to have an axial top length F1_tl extending beyond the tube; and wherein the outer diameter M1_od, the inner diameter M2_id, the inner diameter M1_id and the outer diameter F1_od, the depth length M2_dl, the depth length F1_dl, the top length M1_tl and top length F1_tl are designed such that the male single channel fluid connector is interconnectable both with: - the female single channel fluid connector with the outer collar such that the outer collar is received inside the space, and with - a luer type female single channel connector with a tube for passing of fluid having a threaded outer side with the same design and dimension as the tube and threaded outer side as of the female single channel connector; and such that the female single channel fluid connector also is interconnectable with - a luer type male single channel connector with an inner tube for passing of fluid, and a center collar with a threaded inner side with the same design and dimension as the inner tube and the threaded inner side as of the male single channel connector; and to thereby form a fluid tight single channel connection for passage of fluid. - a male single channel fluid connector designed with an inner tube for passing of fluid, and a center collar with a threaded inner side and arranged concentric with the inner tube, the center collar being defined by an outer diameter M1_od; - a female single channel fluid connector designed with a tube for passing of fluid, the tube having a threaded outer side; characterized in that the male single channel fluid connector is designed with an outer collar arranged concentric with the inner tube outside the center collar, the outer collar is defined by an inner diameter M2_id and an outer diameter M2_od and a space in-between the center collar and the outer collar defining a depth stop, wherein the space has an axial depth length M2_dl; and wherein the center collar optionally is designed to have an axial top length M1_tl extending beyond the outer collar; and wherein the female single channel fluid connector further is designed with an outer collar arranged concentric with the tube and defined by an inner diameter F1_id and an outer diameter F1_od, and a space in-between the tube and the outer collar defining a depth stop, wherein the space has an axial depth length F1_dl; and wherein the outer collar optionally is designed to have an axial top length F1_tl extending beyond the tube; and wherein the outer diameter M1_od, the inner diameter M2_id, the inner diameter M1_id and the outer diameter F1_od, the depth length M2_dl, the depth length F1_dl, the top length M1_tl and top length F1_tl are designed such that the male single channel fluid connector is interconnectable both with: - the female single channel fluid connector with the outer collar such that the outer collar is received inside the space, and with - a luer type female single channel connector with a tube for passing of fluid having a threaded outer side with the same design and dimension as the tube and threaded outer side as of the female single channel connector; and such that the female single channel fluid connector also is interconnectable with - a luer type male single channel connector with an inner tube for passing of fluid, and a center collar with a threaded inner side with the same design and dimension as the inner tube and the threaded inner side as of the male single channel connector; and to thereby form a fluid tight single channel connection for passage of fluid.