I don't have the resources to check their bona fides, but I've been using the Optrel P. Air Clear a bunch for the past six months, and broadly like them. Claims to be N95 certified. Not the largest clear window, but it's not bad (a lot of folks who are hard of hearing have specifically thanked me), and I find breathability decent. Some fogging depending on air temp and such, but not usually terrible. Disposable, but comfortable enough for a full day, and not stupidly expensive, although not cheap.