BUILDMART - 18" Plenum Box for [18" Linear Slot Diffuser - 1 Slot - Single Slot] Premium Insulated Plenum Box for Heating and CoolingGalvanized sheet metal Plenum Box with foam insulation, ideal for Texas Buildmart 18" lineal slot diffuser. This air distribution box attaches directly to the supply of the HVAC equipment that heats or cools the air. Connects to: 8" flexible duct in oval shape. Can be used and brazed to a 4" or 6" wood stud. If you do not have this size flex, you can use a reducer to modify the size. Professional HVAC Installer is Recommended. Ideal for Texas

Total Box Dimensions: L: 36 7/8" W: 3" H: 12"

ASIN: B08F9FCKN3

CFM: 236 ft3/min - Effective Velocity: 9

They have decorative directional dampers

ASIN: B09GJGC36Y

CFM: 295 ft3/min - Effective Velocity: 9

CFM: 301 ft3/min - Effective Velocity: 9

Neck: 25 5/8" x 7 7/8" - Face: 27 5/8" x 9 13/16"

Neck: 13 3/4" x 5 15/16"" - Face: 15 9/16" x 7 5/8"

CFM: 678 ft3/min - Effective Velocity: 9

ASIN: B09GJMZ5P8

ASIN: B085WJK7BZ