Inwin 301 Magnetic Rear Fan Filter Adapter
The Inwin 301 case is a nice case, but the rear fan is better used as an intake. The problem is it doesn't come with a filter, and the case "bumps out" around this area making screwing in a flat filter difficult.
This 3D printed adapter will allow for a better mount of a Silverstone mesh filter. It sticks to the case using magnets for easy dismount and cleaning.
The magnets are pressfit but if they are loose depending on your printer settings, add a dab of superglue.
Printer settings:
Probably use PETG, computers get warm and PLA might soften.
Print with supports, need some small pliers to remove them from the rails.
I suggest adding some horizontal contraction so things don't fit too tight.
Other hardware:
Silverstone 120mm filter: https://www.amazon.com/SilverStone-Technology-SST-FF123W-Filter-Cooling/dp/B00DL4BMVS
4x 8mm by 3mm round magnets: https://www.aliexpress.com/item/32997030821.html