DuPont™ Tyvek® ThermaWrap™ LE is a spun-bonded, non-woven, non-perforated, white-colored polyethylene sheet with an aluminum coating and lacquer protection on one face. DuPont™ Tyvek® ThermaWrap™ LE is designed to manage convective heat flow by providing a vapor-permeable air barrier to reduce air flow through walls. An added low emissivity ("low-e") metalized surface changes the dynamics of radiant heat flow across the entire wall system and dramatically improves the insulating value of the wall system.