A customer purchase heat shrink tubing with glue ( we named it dual wall heat shrink tubing ) from us . 

They share us some pictures of their products be covered with our dual wall heat shrink tubing . We found they are a power adapter manufacturer . 

1. The first advantage of heat shrink tubing . 

   It can apply to irregularly shaped cable . For example , a piece of 3:1 shrink ratio ID 12.4mm dual wall heat shrink tubing can cover on the cable ID from 12mm to 4.5mm . 

2. Second advantage , waterproof . 

   Hot melt adhesive inside can make the able covered by heat shrink tubing airproof and waterproof . It will extend the service life of the cable . 

3. The good extensibility of heat shrink tubing . 

   It can protect the cable from dragging and folding .