BUILDMART - 12 Plenum Box for [12 Linear Slot Diffuser - 2 Slot - Double Slot] Premium Insulated Plenum Box for Heating and Cooling

Ideal for Texas Buildmart 12" Lineal Slot Diffuser - 2 Slot Galvanized sheet metal Plenum Box with foam insulation Total Box Dimensions: L: 13 5/16" W: 4 11/16" H: 11 15/16" Mouth Dimensions: L: 11 7/8" W: 3 3/8" Entry size: 6" flex in oval shape This air-distribution box attaches directly to the supply of the HVAC equipment that heats or cools the air If you do not have this size flex, you can use a reducer to modify the size