This cover slots into the cooling fins of a Deciso DEC740/750. It takes an 80mm fan that slides into the cavity with a slot for the fan's power cord.

I recommend the Noctua NF-A8 5V, Premium Quiet Fan with USB Power Adaptor Cable, 3-Pin, 5V Version (80mm, Brown) (find it on Amazon) as it will have all the connections to use to power off of the USB port on the firewall. The corner vibration pads must be removed for the fan to fit correctly.

This fan effectively lowers the temperature of the case by 25F and is very quiet when used with this cover and the intake duct. (look at my other files for the duct) cover