BUILDMART - 30x4 MUD-IN Air Vent Cover - Drywall Mud-in White Air Vent - Mud Linear Slot Diffuser - Register Grille for Ceiling and Walls - Texas BuildmartOur Standard Linear Slot Diffusers have ASHRAE 70 and ANSI S12. 51 Engineering Certifications Designed and Engineered to the Highest HVAC Industry Standards Commercial Grade Solid Aluminum with Modern Architectural Design This Model can be used in Ceilings and Walls This Model can be used as a Supply Vent Cover and Return Vent Cover CFM: 291 ft3 min Effective Velocity: 9. 8 ft s Neck: 29 1 2" x 3 15 16" Face: 31 1 2" x 5 15 16" This is a Non Filter

12'' X 3 3/4" Linear Slot Plenum Box - For Double Slot (2 Slot) Linear Diffuser - Texas Buildmart - Modern AC Vent Covers for Ceilings

Neck: 7 13/16" x 7 15/16"  - Face: 9 13/16" x 9 13/16"

51 and ASHRAE 70 Engineering Certifications

CFM: 282 ft3/min - Effective Velocity: 9

12" 3 Slot White Triple Linear Diffuser

CFM: 180 ft3/min - Effective Velocity: 9

ASIN: B09JYTXN39

ASIN: B09GJ46L13

30 x 20 30x20 20x30 20 x 30

Ideal for Texas Buildmart 36" Lineal Slot Diffuser - 2 Slot

you can use a reducer to modify the size

CFM 812 ft3/min - Effective Velocity 9