I'm a doctor in Connecticut making 3D printed masks. I heavily modified the one I found that had the largest filter box, as this allows more material to fit inside than any other I have found while still being breathable. Youtube video: https://youtu.be/ySOCNycv-aA I recommend trying the "Mask narrow (male) 2 loop upgrade" and the "Filter Narrow (male)" to go on it, downloadable at https://www.thingiverse.com/thing:4237783 I am working with a local company who is having engineers at Medtronic and DaVinci help me redesign the filter box, so at least that can be injection molded. I am going to make another video very soon suggesting spraying the mask down with sealant to make it easier to wipe, how to sand the edges and options for rubber material that can be added for comfort, and what kinds of elastics work best if you don't have access to IV tourniquets that I'm using for straps. I am also in contact with Harvard and MIT bouncing ideas back and forth about filter material, but I think my design is the best out there in terms of "last resort, better than a bandana" purposes. Newspaper: https://www.theday.com/local-news/20200327/with-3d-printer-new-london-native-develops-alternative-to-n95-face-mask https://www.courant.com/coronavirus/hc-news-coronavirus-3d-printed-face-mask-20200331-dqn67ouibfelrglwri77pvvmcm-story.html Television: https://www.wfsb.com/news/local-doctor-using-d-printer-to-print-masks-for-medical/article_de3a805a-72c6-11ea-887e-db303591745e.html https://www.fox61.com/mobile/article/news/local/a-uconn-doctor-channels-his-medical-background-and-macgyver-skills/520-0c5248f7-f207-4234-80bd-a55b11394117 PROJECT 2: I have another project underway, not yet released, which I am happy to discuss, that uses 3D printed frames to hold on Halyard H600 operating room tray material (idea is from a Florida Anesthesiologist) which can make an n99, being tested now with our frames in our particle chamber at UConn Storrs with excellent preliminary results. This is an adaptation of this mask, but not released yet: https://today.uconn.edu/2020/04/farmington-storrs-team-make-needed-ppe-uconn-health/?fbclid=IwAR32l52kdIOrYKiBxbggvKi0J6ljLjTh6TNSn0nlEKhrhTMbBSiMUTP5Seg