Slip couplings have no central stops, enabling them to be slid along the length of a drainage pipe. This is particularly useful for installations in a confined space, or for use when repairing a damaged pipe.In this instance the damaged section of pipe can be cut out, and slip couplings positioned over the undamaged section. When the new section is lowered into position the slip couplings are slid into position to make the joint between the old and new pipes.