This is Insulated Outdoor Wood Furnace & Boiler 1" ID Pex-Al-Pex Pipe. In all our dual line piping systems there is a layer of insulation between the two pipes. The tubing is also approved for use with potable hot water and with ANY outdoor wood stove. If you have a pump failure or mechanical problem which stops the flow of water in your pipe, this tubing will expand when frozen. It will not crack or break. It can even be placed above ground for mid-winter installations. This insulated pex piping is taped solid from one end to the other so that the insulation remains tight around the pex tubing and keeps your lines hot. Other manufacturers of pipe just tape down the seam and the insulation is loose around the pipe. One of the reasons people buy Pex-Al-Pex tubing is because of its true 1" inside diameter (ID). This allows for alot more flow for those longer runs and those with more heat load. This pipe built with a layer of aluminum between two layers of pex creating a 100% oxygen barrier. The package consists of: a flexible 4" waterproof corrugated plastic pipe (see pictures) two 1" Pex-Aluminum-Pex lines (both orange pipes) triple wrapped low-E closed-cell foil-faced aluminum insulation (see pictures), fully taped from end to end, not just down the seam of the insulation like others do!