I wanted to use my Soviet era GP-5 gas mask for tasks that required particulate filtration (and because it looks cool). The original filter has several heath concerns around its use, so I decided to model a replacement shell to 3D print, which I have included. I then found a Honeywell North P3 filter for another respirator I owned, so I made the filter two pieces and added a thread. 

I have also added a version with a 3M bayonet, but have not tested it.

Use the “Fancy” parts if you intend on adding filters.

A couple of notes:

-This filter should work with any GOST threaded respirator.

-Unless this is just being used for the looks, it requires a low profile Honeywell North P3 filter (compatible with Honeywell and North 5500, 7700 and 7600 series respirators). I used an N7500-8 filter.

-I designed this model with resin printing in mind, so it may be difficult to print on FDM. As well as that, I have not allowed tolerances between the main body and cap, so some sanding may be required.

-The cap just press fits into the body. With the amount of friction resin provides, this is not an issue, however with FDM printing some form of adhesive may be required.

-I take no responsibility for the quality of your print. If your print leaks, and you hurt yourself by using this where a better respirator may have been required, it's on you. Always fit check your respirators to ensure there is no leakage.

-I am adding the Fusion archive file if you want to adapt this to work better for you somehow.