For heat shrink tubes with adhesive or not there are 2 types, single wall heat shrink tube and dual wall heat shrink tube.

Single wall :Thin-walled tube (less than 0.4mm), medium-walled tube (0.5 ~ 1mm), thick-walled tube (> 1mm) 

For single wall heat shrink tube, it is without hot melt glue, the wall thickness is thinner. 

Dual wall :Double wall heat shrink tube 0.4-0.8mm; medium wall heat shrinkable tube  1.1mm thick ;Heavy wall heat shrink sleeve 1.4mm

For dual wall heat shrink tube, it is with hot melt glue, the wall thickness is heavier that single wall. Because of the hot melt glue, it can adhere and protect the goods better. 

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