These shrink wrap PVC battery skins for 18650 batteries.
Batteries must always be in good condition and have their wraps fully intact. A battery can be dangerous and cause a short if the wrap on the battery is torn or damaged in any way.
How to rewrap batteries:
Here are a few simple steps to follow:
Take off the existing wrap from battery*
Put the new wraps around the batteries
Using a heat gun or hairdryer, shrink the new wraps onto the batteries. Becareful not to overheat batteries.
* Do not put the new battery wraps over the existing wraps. The wraps are a specific thickness to ensure efficient heat dissipation so if you put a wrap over an existing one, you may reduce the amount of heat that a battery can get rid of therefore making it dangerous.