Where do you buy your battery shrink wraps for 18650 batteries from? I bought a 50 pack of translucent blue ones from Fasttech and they are too tight- I can't get the batteries in it all the way. I squish the tubes open, finally found two of them that fit. Saving a few bucks is not worth the hour of aggravation- anyone use a brand that will slip onto the battery easily? Called 2 local vape shops and neither had battery wraps for sale- What??????? One of the most important products for safety when vaping and neither had wraps for sale! Terrible!