This coupling is used to join two plain ended pipes together.It can also be used to connect a plain ended pipe to the plain end of another fitting.Whenever any connection is made to a fitting which incorporates a ring seal (push fit) connection, the pipe should always be chamfered and the seal lubricated with silicon lubricant prior to insertion into the fitting.This coupling can also be turned into a slip coupling. 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.To use this coupling as a slip coupling, simply tap out the small internal lugs on the inner central wall of the fitti