RRS 01-530-18 - Side Discharge Concentric Diffuser System with Filter Grill 1,200 - 2,200 CFMDesigned to provide a single point air distribution system with the added benefit of having directional air control. The systems may be used with either a 'T-Bar' ceiling, a plaster ceiling or with no ceiling at all.Standard features include: All anodized aluminum diffuser frame with aluminum return air egg crate. Double deflection diffuser with the blades secured by spring steel. Built-in Anti-Sweat gasket. Molded Fiberglass Transition, through five tons. Built-in hanging supports. Diffuser box constructed of fiberglass ductboard, through 7 1/2 tons or sheetmetal. Stainless steel thumb screws