Re-usable filter cartridge allowing Anesthesia / BVM masks as well as some CPAP masks to be used as an emergency replacement for approved respirators. Includes adapters for various sizes of straps, as typical anesthesia mask straps are not sufficient for ambulatory wear. Designed to print successfully on most common 3D printers using most common filaments, and typical slicer settings, regardless of slicing software used. Tested with PETG, PLA, and PLA+/PLAPro. Prints without supports. Tested to have sufficient filter area for breathing with Halyard H600 surgical wrap used as a filter material. Intended to be generally useful for filter material up to at least 0.2mm thick. Design is parametric, so it can be easily scaled larger for additional breathable area if desired, without any impact on fit. Print Triangle.stl for the respirator body and frame, StrapHolder.stl if mask in use does not provide usable strap fixtures, and SimplusAdapter.stl only if using a Simplus CPAP mask instead of an anesthesia / BVM mask. Ensure that the anesthesia mask fitting or Simplus adapter fitting fits snugly in the hole in the back of the respirator frame. Cut filter material to at least 5mm larger than openings in front and back of respirator body. Place filter material over body, and snap front and back filter frames in place. Trim excess filter material. Frames may optionally be taped together. Place appropriate strap adapter over 22mm air fitting. Insert air fitting in hole in back of respirator frame. (If using a Simplus CPAP mask, insert the large side of the Simplus adapter into the the Simplus mask; the other end is a standard 22mm fitting as on anesthesia masks; proceed to use preferred strap adapter and respirator cartridge as with anesthesia mask. Tape the holes in the Simplus mask. Test the fit of the adapter into the CPAP mask by covering the installed adapter and attempting to breathe in and out; ensure that the fit is air tight.) To clean, remove front and back frames from respirator body, and discard filter material (or sanitize filter material using locally-approved protocols). Sanitize plastic parts using protocols compatible with type of plastic used. Chemical sanitization, UV-A, and UV-C may be appropriate. For parts printed in PETG, ABS, ASA, or other similar plastics, 30 minutes at 70⁰C may be appropriate. Only specialized high-temperature plastics may be autoclaved; no autoclave testing has been done by the designer. Please provide feedback or suggested changes via the gitlab repository: https://gitlab.com/mcdanlj/BVMMaskAdapter Specimens have been submitted to a local facility for bitter fit tests.