The 309-12542 is a red 2:1 ratio flexible heat shrinkable tubing manufactured by HellermannTyton. It has an inner diameter of 25.4mm and an outer diameter of 12.7mm. This tube is used to provide insulation and strain relief for wires, cables, and components. It is flame-retardant and can be used in applications requiring resistance to higher temperatures, including automotive, marine, electronic, and industrial. It features an outer wall that is designed to shrink to the inner diameter of the bundle of wires it is wrapped around. This makes the tubing conform to the bundle tightly, ensuring an electrical and environmental seal is made. The heat shrinkable sleeve supplied with the tubing makes installation easier and faster. The tubing is ideal for eliminating stress and strain on terminations, providing maximum protection from abrasion, vibration and moisture.