do it ourselves gas mask
@0x4d6165 let's do it! Key components are:*silicone or rubber face seal,
*one way valves for input/exhaust,
*Threads for filters, typically with orings or rubber seals
*Eye/face port, transparent plastic
*Adjustable straps with optional counterweight
*Strap anchors, plastic
*Voice diaphragm or mic
*Liquid intake, silicone or rubber
Rubber or silicone parts need to be molded,
Plastic parts would also probably be molded, 3d printing isn't ideal for air tightness. The viewport could be vacuum formed from a flat sheet.