Middle Atlantic DWR-FK22 The DWR-FK22 Rack Fan Kit for DWR 22" Deep Rack (2 Fans) from Middle Atlantic is a fan kit designed for use with DWR series 22 inches deep racks. This kit features (2) 4-1/2 inches exhaust fans, (4) fan guards, and (2) vent blockers. The magnetized vent blockers can be placed over other vents in the rack to promote proper active thermal management with the exhaust fans.