"Dual Wall" is the term used to describe the HeatShrink Tubing that has adhesive on the inside of the tubes. While you heat the tube, the outside will shrink as per normal, however on Dual Wall HeatShrink tubing, it will also melt the "glue" on the inside, making certain your wires will stay put as well as protecting them. The Adheshive also acts as a second lair to the protective nature of heat shrink. So please browse the selection we have here, and all at the same All Battery Sales and Servive - low and competitive pricing, save yourself some money as well.