This is a professionally designed return ductwork installation kit for the BM12MCD and BM18MCD concealed duct (multi room) air handler. With the exception of the return plenum itself this kit includes all of the materials needed to successfully install the BM12MCD or BM18MCD return ductwork. This kit has been designed specifically for the BM12MCD or BM18MCD to deliver an optimal perfomance level and help to simplify the installation. It uses 2 10 inch return ducts to optimize air mixture in your space. It is highly recommended that you select one of the matching supply duct installation kits as well and the supply and return air plenum KIT-BPK12 or KIT-BPK18. This kits is designed to be used with a ductboard plenum such as KIT-BPK12 or KIT-BPK18. This kit is not compatible with a sheet metal plenum. It includes:  

x2 25 feet of 10 inch R8 metalized felx duct
x2 10 inch ductboard takeoff collar no damper
x2 12 x 12 x 10 (round connection) R8 insulated ceiling boxes
x2 12 x 12 x 1 ceiling filter grille
x1 Foil tape

Installation notes: The opening in the return box needs to be flexed open a bit to accommodate the filter grille. Also, the flange of the return box is larger than the grille and will be visible from inside the living space. The return air box flange can be trimmed so the grille covers it fully.