Creality K1 K1C HEPA + original Active Carbon Filter housing.

I couldn't find a filter housing that held the original carbon filter plus a Ø80mm HEPA unit. The HEPA filter used is from a Roidmi NEX X20 X30 S2 F8 Storm Pro , which I purchased from Aliexpress at £2.50 for a pack of 2, but they were also available on Ebay & Amazon. Comments from others with similar filters say that the fan isn't strong enough for this application, but with it fitted and the fan running I did a smoke test with a match and there is flow through the filter, so it will be enough to keep air flowing through the chamber when required. The HEPA filter fits nicely into the holder to provide an airtight seal and the holder was a snug fit onto the original mounting point. I printed this using Hyper PLA, 0.6mm wall, 20% infill.