Dual wall heat shrink tubing is medium insulated polyolefin tubing. Dual wall shrink tubing is flexible and flame retardant. The tubing wall is made of modified polyimide adhesive that melts and flows, encapsulating and sealing components contained within the shrink tube. Dual wall tubing features a 3 to 1 shrink ratio, and provides excellent protection from fluids, moisture and corrosion and is useful for the outdoor, automotive and marine industries.