Locate fans directly above vents on hot equipment to get the hot air moving.Innovative sliding rail system allows positioning of the tray at the front of the rack or towards the rear to match equipment vent locations. Can also be mounted front-to-back if desired to better match vents.Uses from 3 to 8 quiet 4" DC fans (69CFM per fan)8 fan mounting positions let you locate fans exactly where neededEnergy saving thermostatic control for automatic on/off when neededPowered by a single cordUses only one rackspaceAdjustable mounting range of 18" to 32"Thermostatically Controlled fans turn on when the temperature reaches 87° F/30° C, and turn off at 85° F/29° C