BUILDMART - 36" Plenum Box for [36" Linear Slot Diffuser - 2 Slot - Double Slot] Premium Insulated Plenum Box for Heating and Cooling

Ideal for Texas Buildmart 36" Lineal Slot Diffuser - 2 Slot Galvanized sheet metal Plenum Box with foam insulation Total Box Dimensions: L: 36 7/8" W: 4 5/8" H: 11 7/8" Mouth Dimensions: L: 35 3/4" W: 3 1/4" Entry size: 10" 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