SCD type ceiling diffusers has been designed to handle a wide range of airflows and maintain a high quality of air diffusion in occupied spaces. The SCD series can be used for supply, return and exhaust air applications. Because this type of air outlet discharge horizontally near the ceiling, the warmest air in the room will mixed immediately with the cool primary air far above the occupied zone. Therefore, this type of air outlet is capable of handling large quantity of air at high temperature differentials. It has a pleasing appearance that suit to any type of ceiling to match the architectural design.