Round LED bay lights install in new lighting layouts or upgrade existing HID installations to LED. They convert to LED one fixture at a time, match the existing lighting layout, and maintain a consistent look. LED lights use less energy and typically last longer than HID lights, reducing maintenance and downtime. Also called UFO lights, round bay lights are commonly used in older buildings where overhead ducts or pipes prevent the use of linear bay lights. Bay light fixtures deliver bright, uniform illumination from high ceilings or open trusses to floors and work surfaces below. They mount at greater heights than other types of overhead indoor lighting fixtures to illuminate warehouses, factories, gymnasiums, hangars, big-box stores, and other large, open spaces. Mounting height (high or low bay), height of the work plane (floor or elevated surface), light distribution (narrow to wide), and lumen output are key factors for selecting a bay light.