Does what it's meant to do!
I found this a little confounding the first time I put it on, but after that (and after watching the helpful video) it was pretty self-evident what goes where.  Still, this isn't something you would want to have to put on in a hurry, like to answer the doorbell; it's more in the nature of a device you would put on before going to the store or to work.  Most important, though, when properly worn the device does what it's meant to do: provide a much improved seal around the edges of the mask, thereby directing air flow to the center of the mask.  In that respect, it's the only product I found that serves that very important purpose.  Furthermore, my experience is that it eliminates the problem of glasses being fogged up by your exhalations, which is a big deal for me as a glasses-wearer.  The device itself appears sturdy, although I've only had it a short time.  Overall, well worth the price.
Rating: 5 stars