THERMOFLUX is a flexible, heat shrinkable dual wall tubing with an integrally bonded meltable adhesive inner lining, designed to provide permanent moisture proof encapsulation to a wide variety of substrates and uses. THERMOFLUX has a unique inner wall which melts when heated and is forced into the crevices and interstices by the shrinking of the outer wall. When cooled the entire mass becomes a flexible, tough homogeneous covering with a controlled wall thickness. THERMOFLUX is manufactured from radiation cross-linked polyolefins. THERMOFLUX shrinks to 1/3 of its supplied diameter and thus only a few sizes (8) are required to cover a full range of irregular shapes in a wide variety of applications.