John Guest's Pex Barrier Pipe in Coils are manufactured in the UK by John Guest Speedfit. Our PEX pipe is made of 5 layers, the centre of which is a blue coloured oxygen barrier which prevents the ingress of air into the system, reducing the effect of corrosion on metal components. Due to its low thermal conductivity, when carrying hot water, a Speedfit pipe is cooler and therefore safer to touch. Note: JG Speedfit pipe inserts must be used.