A range of compression fittings to join yellow gas MDPE pipe together and for transition; i.e. to join yellow gas MDPE pipe to steel pipe (pipe to BS EN 10255:2004(BS 1837:1985), and a range of compression fittings for yellow MDPE gas service pipes ; for new installations or repair work. The fittings are tough, fully end load resistant, and corrosion free. ‘O’ ring displacement or loss during installation has been eliminated.