Get the “World Flex Insu” air conditioning insulator with a diameter of 3/8 inch and a width of 3/8 inch. This insulator is ideal for use in air conditioning systems to provide effective thermal insulation and protection from thermal leaks. Brand: World Flex Insu. Size: Diameter 3/8" long, 3/8" wide. Use: Ideal for insulating ducts of air conditioning systems to improve energy efficiency and reduce heat leaks. Material: Made of high quality insulating materials that provide effective insulation. Durability: Durable and withstands various environmental conditions.