3-to-1is a semi-flexible, cross-linked polyolefin heat shrink tube that possesses a meltable inner lining of adhesive that flows when heated. In addition to insulation and mechanical protection, this tubing provides a moisture-proof seal for wires, splices, breakouts, and components.  Adhesive lined heat shrink has a 3-to-1 shrink ratio and is flame retardant (except clear).