Heat shrink tubing is available in three main types: single wall with a shrink ratio of 2 to 1, dual wall with a shrink ratio of 3 to 1, and Heavy Duty with a 3 to 1 shrink ratio. All of our tubing is made from durable polyolefin. Single wall heat shrink is our most popular tubing. It is available in sizes from 1/16 inch to 2 inches in diameter. It is sold as either 4 foot sticks or on larger length spools. An assortment of colors is also available, as well as see-through clear. Our dual wall heat shrink tubing is designed to be more durable, has a shrink ratio of 3 to 1, and comes with an adhesive lining that will seal as it shrinks, providing environmental protection. Dual wall is available in black, red, and clear, and comes in 4 foot sticks with sizes from 1/8 inch to 1 1/2 inch diameters. Heavy duty heat shrink tubing is our toughest and most durable heat shrink with a 3 to 1 shrink ratio. It has an adhesive lining as well, and is often used for covering battery cable connections or where maximum protection and sealing is required. It comes in 0.4 inch to 1 1/2 inch diameters and is available in 1 foot and 4 foot lengths.