There are many wonderfully creative implementations of n95 masks and fabric holders, some of the most popular being from the Billings, MT and LowellMakes in MA.  As a collaboration between the Jeremy Ralston, Engineering Manager of the SLO Surgery Center, Cristian Sion, a Cal Poly Engineering student, and Clint Slaughter, MD, a local ER physician with Vituity, French Hospital ER, and SLO MakerSpace, we were able to bring the independent work we were each doing into a single project that remixes some other designs into a community mask alternative. 

We have modified the Billings community mask model to include a larger filtration area for better airflow, an extended chin area, thinner walls to allow heat-molding to a user’s face, and added a cap similar to the LowellMakes mask to allow the entire mask to be sanitized between patients.  This provides a safe, effective, and locally producible way to markedly extend the supply of n95 masks.

This n95 holder is able to achieve subjective n95 fit testing on a wide variety of people, with the fit adjustable by heat molding and the installation of weatherstripping for comfort and an improved seal. This is not a NIOSH-approved device, but it functions as a holder for NIOSH-approved n95 material and we therefore consider this an extension of already approved equipment, which may allow for easier approval at your site.

The mask can be 3D printed on home machines, any elastic, rubber band, or similar can be used for straps, and either properly handled used n95 respirators or new n95 disposable respirators can be used to make 1-4 SLOR masks.

 

edits from Natronwong 

 

Summary

Instead of printing the full mask only to find out it doesn't fit you well, print these different "sizes" to try out. The original mask can be scaled in the X and/or Y planes to get a perfect fit for you. For example, I found that if I scaled it to 90% in just the "nose to chin" dimension then it was a perfect seal for me.

The sizes I uploaded called 100%, 90%, and 80% are scaled in both X and Y dimensions. The size called 90% wide is only scaled down in the "nose to chin" dimension. The width is the same as the original. This was a perfect fit for me personally.

Alternatively, you can use this Mask Rim over a surgical mask to enhance the fit and seal of a basic surgical mask.