Heat shrink is the duct tape of electronics which we guess makes this heat shrink the colorful and exciting duct tape they sell at craft stores.  This pack contains heat shrink tubes in five different colors - red, blue, aqua, yellow, and the classic Adafruit black.

Each pack contains a wide variety of ~45mm pieces in the following sizes: 12mm, 9mm, 7mm, 6mm, 5mm, 4mm, 3mm, and 2mm. It's a nice colorful mixed pack of heat shrink in a portable, reusable storage container!

Heat shrink keeps your stuff all safe and kept together. Especially when wiring and soldering, you use heat shrink to add mechanical strength to cables. We use this stuff all the time and having a box of all the possible sizes is super handy. The colors can be used to color-code different wires, so you know which wire is power, data, ground, analog in, etc.