Montana Mask Edit

This is a redesign of the popular "Montana Mask" designed by Dr. Dusty Richardson, Dr. Specer Zaugg, and Colton Zaugg found at https://www.makethemasks.com. It addresses the problem of mashing a filter into a square hole, potentially damaging the filter. To use this design simply place a 3 inch diameter filter over the hole, secure it in place with the filter retention body, and screw on the cap to create a tight seal.

Edit: V1.2 maintains the same overall design but increases the diameter of the breathing hole from 4.0cm to 5.2cm, effectively increasing the filter surface area 70%.

Edit: V1.3 increases the diameter of the breathing hole again to 6.2cm for easier air flow. The hole size for the straps was increased.

Parts from different versions will not work together.

Thanks to u/hazeldazel and u/PonderingWalnut on Reddit for helping verify v1.3