Rack Mounts Plugsters rack mounts store a large amount of adapter panels in small spaces.FRM -E-1RU 3 panels, 1.75″H x 17″W x 13.87″D, 19″ Rack, 23″ Rack Rack Mount FDU 1RU in height with split top design and slide out master panel tray. FRM-E-2RU 6 panels, 5.21″H x 17″W x 14.51″D, 19″ Rack, 23″ Rack Rack Mount FDU 2RU in height with 6 termination panel capacity and slide out master panel tray. FRM-E-3RU 9 panels, 5.25″H x 17″W x 16″D Rack Mount FDU 3RU in height with 9 termination panel capacity and slide out master panel tray.FRM-E-4RU 12 panels, 6.96″H x 17″W x 14.51″D, 19″ Rack, 23″ Rack Rack Mount FDU 4RU in height with 12 termination panel capacity and slide out master panel tray.