Aluminum Couplings are made using a 6061-T6 typical alloy. This product has left and right internal threads allowing installation to be accoplished by rotating in a single direction while pulling each duct toward the center of the coupling. There are many sizes available as well as transition couplings from one duct size to another. FO9006 1.315 Duct O.D. Standard reverse thread aluminum coupling. FO9010 1.66 Duct O.D. Standard reverse thread aluminum coupling. FO9013 1.90 Duct O.D. Standard reverse thread aluminum coupling. FO9019 2.375 Duct O.D. Standard reverse thread aluminum coupling. FO9098 3.50 Duct O.D. Standard reverse thread aluminum coupling. FO9100 4.50 Duct O.D. Standard reverse thread aluminum coupling.
