There are many designers on the Internet. Designing water repellent hoods and anti-fog hoods for the 501 of the 3M gas mask are very powerful, but unfortunately, most of them cannot be tested for sealing after being installed because the hands cannot be completely covered. In the original wearing instructional video, it is mentioned that after wearing a gas mask, you need to cover the air inlet with both hands and inhale. Test whether the gas mask is worn properly and the seal is good. The air outlet should also be tested to see if there is a leak. The only cover I think can be used by only one designer (modbus_TCP), but what he shared is for the higher-order canister 60926. The frame of 60926 is relatively narrow, so it cannot be applied to the 3M 501 cover. I imported the STL into Tinkercad for modification. Simply adding width and adding 4mm thickness can be mounted on the 3M 501. The disassembly and assembly are all aspects, so the process is to wear a gas mask,seal check, and then the splash-proof cover can be snapped on.Thanks, modbus_TCP.