While most of the cable designs customers send our way don’t even specify a particular heat shrink type — merely “heat shrink tubing as required” — heat shrink characteristics can affect cable performance.   If you need to cover a splice point on a cable that will be outside, we’d recommend a dual-wall, adhesive-lined heat shrink tubing instead of single-wall heat shrink without adhesive. The reason: Water can breach single-wall heat shrink and cause your cable to fail at the splice point. Dual-wall heat shrink offers additional resilience against the elements.