These defrost ducts are an excellent choice when the original heater defrost ducts are missing or cannot be used. .?Made of high impact ABS plastic with a smooth finish. .?Holes added for attachment on each side of duct for easy mounting to your classic muscle car. Flex hose attachment designed for 2in. duct hose. Fits nicely when adding A/C in street rods and other classic car or truck applications where room may be an issue.