The reflective product BOLTHERM is composed by two external aluminium films (min. 99% of purity) cover with an external coat of PET (polyethylene terephthalate) and other of PE (Polyethylene) of emissivity 0.4, linked by a thermo-welded to several internal layer of polyethylene. The total thickness of the product goes from 5.0 to 20 mm.