Replace old worn covers or just get rid of horrible battery cover colours.
72mm x 31mm flat
These are very tough and will protect your batteries from damage.
Simply
place battery inside leaving equal lap either end and heat up with a
heat gun or hairdryer the wrap will shrink to perfectly cover your 18650
battery.
PLEASE MAKE SURE YOU DO NOT OVERHEAT WE DON'T WANT ANY ONE COOKING BATTERIES!