Couldn't find a filter housing that fit the original carbon filter and hepa filter for the K1C, the carbon filter will be a little tight but it cuts the smell from PA. there might be a couple of little pieces that cover the interface slots just break them off

I used this refillable carbon filter from onky tonky https://www.printables.com/model/988768-creality-k1c-k1-refillable-carbon-filter

and the hepa filters from amazon https://a.co/d/2atPXfl

Inspiration from Onky Tonky https://www.printables.com/model/994337-creality-k1c-k1-hepa-filter-adapter