I bought this to protect myself from the sun during long running/cycling sessions. For many reasons, I do not like sunscreen, so I was looking for a physical solution. The product is quite elastic and fits securely around my large head. It is also long enough to cover my entire neck and upper-collarbone region; wearing the right shirt, I am able to tuck it under the shirt collar. My biggest concern was whether it would be too restrictive of breathing to be used for a workout. The trick in designing these things is in the air holes; picking the right number of holes and their sizes creates a trade-off between breathability and UV protection. This mask gets the ratio pretty close to what I need. I was able to run 6 miles, without struggle, in this mask and didn't notice any tanning around my mouth. YMMV, of course. The product dries very quickly too, which I noticed because I leave it out in the sun to dry and disinfect (UV great for killing bacteria) after my exercises. I highly recommend this product.