The 164-OSN 04X10 is a 04 inch x 10 inch 1 way air diffuser used for floor openings. The crafted ornamental scroll design is perfect for your decorative needs. This patented smooth glide technology ensures your dampers are quiet airflow from your central air system. Smooth glide also provides for smooth opening and closing of your back dampers. This high quality product will ensures years of continuous use.