MDPE x MDPE Polyfast & Floplast Supreme compression fittings, with blue nuts and black bodies, for joining MDPE (blue or black), LDPE, HDPE normal gauge and heavy gauge pipe. Connections can also be made to copper and lead pipes. As supplied, the fittings may be used on blue MDPE to BS 6572 and black MDPE to BS 6730. A plastic pipe stiffener (P/N 9922-9926) must be inserted into the bore of the MDPE pipe before use. For use with black LDPE to BS 1972:Class C and D, and black LDPE to IS 134 normal gauge ; the relevant insert adaptor sets must be used. Adaptor sets for connecting copper pipes (to BS 2871 Tables X and Y) and lead pipes (to BS 602, 1085) to polyethylene pipes are also available.