Remix of stepper driver cooler duct to fit the Mellow Fly F407ZG 9 stepper board
https://github.com/Mellow-3D/FLYF407ZG
Seems to work fine, although cooling performance is highly dependent on the direction of stepper driver heatsink fins.
The author remixed this model.
Adjusted to fit the Mellow Fly F407ZG 9 driver board