Galvanized Top Takeoffs The most commonly used fitting for starting a round duct run off a residential duct system. SKU 4TTO Product Details | Specifications | Check Inventory Please select 4" TOP TAKEOFF 40/CTN 5" TOP TAKEOFF 30/CTN 6" TOP TAKEOFF 18/CTN 7" TOP TAKEOFF 12/CTN 8" TOP TAKEOFF 10/CTN Log in to view price