The last mask filter was threaded for NATO and GOST filters, meaning the threads weren't exactly Ideal for the GP-5 mask I made it for, so I took bluepug's threads, thank you by the way, and made some quick fixes as well as adding some new hole shapes to let air in, I made all these fixes in Tinkercad online, so it isn't exactly professional level, but it works and looks good.
You can fill it with something like cotton to keep debris from getting in, but I suggest you put cloth or mesh at the bottom to keep it from coming out of the holes in the larger filters.
Once I fix my nozzle and print another in white PLA I'll post pictures.
PRINT IN SEPARATE PARTS, THE FILE Fantabulous_Waasa-Turing_5.stl IS FOR SHOW AND IS NOT FUNCTIONAL.
The infill doesn't really matter, as long as it's above 50%, but the more the better.