Don't want to suck hot carpeted air, dust and dirt into your expensive GPU and case? Want cooler temps and higher airflow? Use these ducts to pull air in from beside the case not directly and immediately beneath it. Position them pointing either side, though they are sized to just peek out from the glass side on a Lian Li O11 series of case.
Likely fit any 120mm fan mounting on any case, sized to minimally do the job. Optionally add in a slim 120mm Fan Dust Filter between the duct and Case to further stop dust ingress. Use 20-30mm wood screws or similar (or long versions of the standard PC Fan screw) to screw straight into fan on other side.
Recommend Printing either with the two small openings on print bed (ie vertically) and minimal supports (or none) OR with the either the top or bottom on bed an deal with supports. Interior is tapered and filleted as much as possible for strength and also printablity.
The author marked this model as their own original creation.