11-1/4" x 11-1/4" Plastic Air Return with built-in damper. A unique plastic ceiling air return which incorporates an integral ceiling box. Intended for residential and light commercial applications. They provide maximum convenience and timesaving as they are designed for easy installation by one person only working from below the ceiling. Included is a built-in Air Damper to restrict air flow when desired. Used for a 4",6" or 8" duct.