A 45mm or so long duct to connect the QIDI Q1 Pro's print chamber 60mm internal fan to the vent at the back to allow hot air to escape without heating up the electronics.
The original idea was based on the model below, only as I have my machine connected to an external duct, I don't need the activated carbon or the grills in the way causing restrictions and I didn't need a lid for it either. So used it for some of the basic dimensions and the idea but otherwise is a new model.
https://www.printables.com/model/861717-qidi-q1-pro-activated-carbon-box
For an external duct, I suggest this model:
https://www.printables.com/model/826987-qidi-q1-pro-rear-mount-60mm-air-hose-adapter
This allows it to be connected to the outside world or to an external carbon filter if you are printing ABS/ASA or other off-gassing filaments.
The author marked this model as their own original creation.