The roof ventilation units are variable mountable into 483 mm 19 cabinets each fan unit comes with two sets of mounting brackets with the standard set you can install your fan unit into any height unit space of your network or server cabinet the second bracket set makes the fan unit possible to be mounted into the roof of 483 mm 19 network or server cabinets of the varioflex series a switch as well as an adjustable thermostat provide best options for customizations the model is ava