[4:1] Higher shrinkage, thicker double walls, better quality liner glue, higher flame retardancy, and less restrictive range of use.
[Professional] 4:1 automobile special grade heat shrink tube, special white hot melt adhesive, better sealing, and keep your equipment safe for a long time.
[Convenience] For some devices that need to be cut and put into the heat shrink tubing, 4:1 can save you these troubles.
[Better protection]: double wall heat shrink tube and lined with glue can better act on the wrapped objects.