Ducting 4" and 6" - Lumen Farms Lumen Farms Growing $20.99 4 inch - $20.99 6 inch - $29.99 Quantity This variant is currently sold out Please fill in the form below if you'd like to be notified when it becomes available. 4 inch and 6 inch ducting by Lumen Farms. 7.6 meter length (25 feet)