The "Cambridge" masks have a store front on Amazon but are backordered into August and not listing anything. I doubt their claim as well.

Amazon has gone way downhill in quality of their sellers/providers over the years. Especialy the last year or two. It isn't much better than eBay in the Trust category. You have to read a lot of reviews and get past the paid for ones.

All of the mask tips shared in this thread I already knew, but is it a good review for anyone who hasn't done their homework.

Still looking for a good source.

Stay healthy.