The Rapid 24947500 is a set of 34 pieces of 2:1 heat shrink sleeves. Heat shrink sleeves are a type of electrical insulation, a protective covering that slides over wires or cables to protect against abrasion, moisture, and other environmental factors. These sleeves are made from a heat shrinkable polyolefin material with a 2 to 1 shrink ratio, meaning that they shrink to half their original size when exposed to heat. This product is ideal for insulating, bundling, and repairing wires and cables.