Mega-fan 4-Zone AV Cabinet Digital Thermostat-controlled multispeed cooling fans This cooling system is designed to be mounted in your enclosed equipment cabinet or computer desk. It will quietly exhaust the hot air outside, or pull cooling air into the cabinet, or both -- you choose how it is set up. It has 4 high-quality, low-noise 120mm fans, with long-lasting and quiet fluid dynamic bearings. Each fan has its own mounting plate, to facilitate installation. The system also includes an adjustable digital thermostat. In addition, YOU control the fan speed, using the multi-speed fan controller. Recommended fan speeds for this system: The fans (running together) are rated at 22db while moving 196 cubic feet of air per minute (2/3 speed), or 25db & 220CFM at 3/4 speed. With cabinet cooling, slow (and quiet) are the way to go! Other available speeds: 1/3 speed = 16db/100CFM, 1/2 speed = 19db/144CFM, Full speed = 28db/296 cubic feet of air per minute. The cooling units measure 6-1/4" square (includes the mounting plate), and the required mounting holes are approximately 4-7/8" square.