Wall plate elbows are generally used to connect an MDPE pipe to an outside tap (Hose Union Bibcock).The 20mm MDPE pipe is connected into the compression end of the fitting. The flange of the fitting is screwed back to a support such as a post or to brickwork, and the hose union tap which has a ½” BSP male thread is then screwed into the female socket of the fitting.Pipe liners (or stiffeners as they are sometimes called) should always be used at the MDPE end of the fitting.This fitting is WRAS approved. All of our MDPE fittings can be used on either blue (potable) MDPE pipe or black (non-potable) MDPE pipe.