What is the opinion of Reddit about the
50 PCS PM 2.5 Filters Activated Carbon Filter Replaceable (50 pcs)?

I was buying the industrial ones at home depot before corona. The pm2.5 filter sheets sold online like this example fit fabric masks with a filter pocket. I have been using ones like this with some fabric masks I bought last year. I haven’t used this seller, but this is the kind of replacement filters my mask uses for the ones I wear that have filter pockets.