We use it for light sanding, cutting wood boards, and emptying out the ash from the wood stove. The metal clasp goes over the bridge of the nose and on the inside directly opposite there is a strip of foam to aid in keeping any additional dust out. The two elastic straps are fastened pretty securely. One strap broke away from the mask when during the winter we tried to pull it up and over are hats. The mask itself covers the face, leaving no gaps whatsoever. While it's not 100% effective it's an inexpensive alternative to the professional respirators.
Adjustable fit for protection around nose. Glad I purchased a box +10 years ago before we heard the term Covid. Elastic bands still strong and masks fit snug. Happy I do not need day long protection but use less than an hour per week.