Heat shrink is the duct tape of electronics, it keeps your stuff all safe and kept together. Especially when wiring and soldering, use heat shrink to add mechanical strength to cables. We use this stuff all the time and having a zip-lock bag of all the possible sizes is super handy.Pack contains four 6" pieces of the following sizes: 3/32", 1/8", 3/16", 1/4", 3/8", 1/2"2:1 shrink ratioHigh-grade flexible polyolefin materialUL approved