Propane labels sometimes called Sleeves or Wraps, are a marketing and safety tool for the exchange propane 17 to 20 pound tank label industry. These labels are made out of low density polyethylene, three mil in thickness. They slide onto the tank without any heat , using only a film additive called EVA. This film additive allows the plastic to stretch in a small percentage to that similar of a rubber band.
The under sizing of the material allows them to snap back and hang onto the tank.