Weil-McLain AlumiPexR tubing is a three-layer composite pipe consisting of an inner layer of cross-linked polyethylene (or PEX), a layer of aluminum, and an outer layer of PEX, all bonded with adhesive during extrusion. The inner and outer layers provide protection against corrosion, and the aluminum layer prevents oxygen penetration. It is available in 300-ft. and 1,000-ft. coils. www.weil-mclain.com Weil-McLain.