Heat shrink is a device used in cable and wire management. It is created from a material specifically designed to shrink to a predefined ratio to form a tight, seamless bond around wires and cables. Boots and caps are particularly designed to fit over the wire and connector terminals to help secure the connection or to cap off and protect wires or cables. To select the proper boot or cap, you need the shell size, supplied diameter, and recovered diameter. Other defining properties are the color, type, and length. These have many special feature options such as: abrasion resistant, adhesive coating, chemical resistant, fluid resistant, heat resistant, strain resistant, flame retardant, etc.