An ostomy coupling has one coupling element 10 attachable to a medical grade pad and a second coupling element 30 attached to a bag or pouch. In such a coupling a stretchable ring or wall 36 can be shifted ("snapped") by manual pressure between a locking position e.q. Figure 4 wherein the two coupling elements are locked together and an unlocking position e.g. Figure 5 wherein the two coupling elements can be separated to permit removal of an ostomy bag attached to one or other of the coupling elements.
