This Fan Holder can be set in a angle which gives a good option to focusing the airflow easier.
The Fan size is 40x40mm and the mountingHolls are 2,8mm
(with a 32x32mm size from Hart to Hart).
It's included with a MountingPlate which use a "LookLike" GoPro mount connection...(the Through-Holl is 4,1mm)
All parts can be printed without Support ;-)