3:1 Shrink Ratio. Heat Shrink Tubing that is suitable for a variety of Low Voltage (2500 Volt and Below) Electrical and Mechanical Applications, where lighter weight and greater flexibility are important. Seals and Protects Cable Splices and Terminations. High Resistance to Impact and Abrasion. 4' Medium Wall Heat Shrink Tubing has Thermoplastic Adhesive Liner for Complete Environmental Protection and Insulation.