This is a PWM controller. It will pulse the power to the fan, varying the speed from the knob. Ali express: https://www.aliexpress.com/item/1005001333983887.html?spm=a2g0o.order_list.0.0.71cc1802l0WvKo
There are two parts. The knob press fits into the mount I made. The control board screws into the board mount using M3x6 screws. Use VHB tape to affix both parts to your printer.
The author hasn't provided the model origin yet.