FITMENT: Perfectly fits 4" x 12" duct openings, ensuring a precise match. It is essential to measure your duct size, as the register size corresponds to the duct opening before buying vents covers or registers. COMPATIBILITY: Vent covers are designed for use on floors DURABLE: Floor vent is composed of heavy duty steel with a white powder-coated finish which is flake resistant and provides a longer-lasting performance FUNCTIONALITY: This register vent cover is designed to improve air ventilation in HVAC systems, and features an adjustable damper to easily control air flow EASY TO INSTALL: Vent cover registers are easy to install, Just drop in the place. No tools required