Bubble foil insulation is a major part of our business at MWI Components. Bubble foil insulation comes in single or double bubble with either a layer of foil on both sides or foil once side and white  poly on the other.  Widths available are from 4' to 10' and standard lengths are 125'  The foil side will reflect up to 98% of radiant heat.  Great for use on post frame and metal frame buildings as well as under metal roof's on houses.  Buildings with foil insulation will be much cooler.  The product also serves as a great moisture barrier.