The Hydrofarm Radiant is designed to deliver the brightest possible light down to your plants. The patented double-wall design and generous reflective cavity make it the coolest running fixture on the market. Constructed of heavy-duty pre-galvanized steel and lined with high-purity European aluminum, the Radiant will give years of dependable growing performance. 21" Long x 21" Wide x 9 3/8" Tall