The shrink wrap is for covering your custom battery packs as well as other productsFor the best result use Hot Air but if there is not Hot Air available you can use a hair dryer to evenly heat up the wrap to shrink until it is tightly wrapped around the battery pack.It's approx 0.1mm thick with approx. 2:1 shrink ratio.Shrinking rate: cross section: 48% +/-5; longitudinal: 15% +/-3Shrinking temperature: 80 Celsiusblack)Flame RetardantLength:2mFlattening Width: 120mm (diameter of about 76.39mm)Colour:blackMaterial:PVCPackage Contents: 2x Heat Shrinkable Battery CoverOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.