Premium Wire Protector: Our heat shrink tubes are perfect for appliance/auto electric wire cable harness wrapping, which will be exposed to harsh environments. They can be also used for solder joint protection, group of lines marking, resistance electric capacity reason protection etc. Note: Make sure temperature of your heat gun is up to 212℉(Fahrenheit), then glue inside will soften and seal the connection. Good Tightness with Glue Lined: Our heat shrink tubing has the advantages of good electrical insulation, good tightness and corrosion resistance, High temperature resistance. Especially the Heat activated adhesive lining provides impermeable seal to salt water and other liquids, which hase better performance when you DIY. Safe & ECO-Friendly: Our heat shrink tubes are UL certified for up to 600V, 257 degrees Fahrenheit which ensures its safe and reliable. They are also RoHS Compliant, protect you and your famaily from toxins. Fast & Easy Use: Are you bothered by the fact that wrapping cable wire connection with electric tape which is ugly and not safe enough. Now the good news is that our heat shrink tubing can avoid these troubles and give you a tidy connection. It is 3:1 heat shrink ratio, and will shrink up to 1/3 of original, only use a hair dryer or heat gun heating it.