American Metal 356W12X4 12-inch x 4-inch Steel Wall Diffuser - 1/3-inch Grille B
Varied dispersion for cooling or heating Adjustable multi-louvers damper Three bars to the inch Gasket equipped All steel construction White finish 12" x 4"
American Metal 356W12X4 12-inch x 4-inch Steel Wall Diffuser - 1/3-inch Grille B Review
You can't find better for price under 13.20.