John Guest Speedfit MDPE Elbows, this new range of fittings for MDPE Pipe fitting has an improved collet with stainless steel teeth to provide extra grip on the pipe and has WRAS Approval. The procedure for connecting and disconnecting the fittings is similar to that for speedfit plumbing fittings. Pipe inserts must be used in every connection, Inserts do NOT come with fitting. Cold water only.