4" X 20" Or 20" X 4" Heavy Duty Floor Grille - Fixed Blades Air Grille - Brown [Outer Dimensions: 5.75 X 21.75] Height_22in + Product Details Perfect Fit

+ Product Details Perfect Fit & Easy Sizing - Designed for a 12" x 36" or 36" x 12" duct opening (measured at the opening)

+ Product Description Secure your thermostat with the heavy-duty Beige Metal Thermostat Guard

Slots Are Angled to Diversify The Airflow In 2 Way Direction - Great for Wall and Floor & ceiling Applications

the second number represents the width

4" X 20" Or 20" X 4" Heavy Duty Floor Grille - Fixed Blades Air Grille - Brown [Outer Dimensions: 5.75 X 21.75] Height_22in + Product Details Perfect Fit+ Product Details Size 4"w X 20"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 5. 75" width X 21. 75" height. High Quality High grade steel construction meant for high foot traffic areas. Installation Location Floor. Design Easy drop in installation. Powder Coat Finish Smooth, shiny, scratch resistant, with no sharp edges. Looks like it was just waxed. Quality Packaging Carefully shrink wrapped