Don't stay in place
When I ordered these didn't know much about them and now I see advertisement for ones that fit onto any mast better. The concept was good, keep it off your nose and mouth but they don't stay with the mask even after I double taped them to the mast. Cumbersome.  I've seen some that hook to the top and bottom of any mask and that is what I'll research next. But these were as advertised.
Rating: 2 stars