Hart & Cooley 14" x 25' R-6.0 Flexible Insulated Air Duct Connector (Flex) #051319 Hart & Cooley 14" x 25' R-6.0 Flexible Insulated Air Duct Connector (Flex) #051319 Black polyethylene jacket GREENGUARD Level 4 highly microbial resistant Double-ply, black polyester core 12" W.C. positive, 1/2" W.C. negative