The Square Plaque Diffuser (SPD) has a flush appearance, making it ideal for architecturally-conscience commercial spaces, and provides industry-leading low pressure drop and sound generation with a 360° radial, horizontal air pattern for rapid mixing and optimal thermal comfort. The one-piece, aerodynamically optimized backpan maintains the horizontal air pattern even at low air volumes, making it a great choice for high turndown VAV applications. This versatile diffuser is easy to maintain, with little to no ceiling smudging and a tool-free removable face for quick access to dampers, accessories, and ductwork.