Likely to be found just about anywhere there are cables and wires, heat shrink is extremely useful, both for protection and cosmetic enhancement. It can be used to:
Seal water and dust out of cable splices
Insulate cables and wires against extreme heat in aircraft, boats, and military vehicles
Provide a barrier between cables and corrosive chemicals
Color code cables for easy identification
Harness multiple wires together
Make long-lasting labels for network patch cords