3M™ Heat Shrink Tubing MW is a semi-rigid, 110 °C (230 °F) heat-shrinkable polyolefin tubing that is co-extruded and selectively cross-linked to provide an integral, meltable inner wall. When heated in excess of 135 °C (275 °F), the inner meltable wall of the tubing is simultaneously softened and forced by the shrink action into intimate contact with all underlying surfaces, interstices and small voids. - Upon cooling, the MW tubing provides a tough protective and insulating barrier, highly resistant to penetration by moisture and the attack of chemicals and solvents.