This is a mask made of smooth stretchy material that fits over your lower face and neck much like a gaiter, but looser and more comfortable. The product page notes that it is for a dog groomers, but can be used for many tasks where there is dust or debris in the air - it is ideal for woodworking or leaf blowing. It's great for keeping out large particles, but would still recommend a proper mask for tasks involving cement dust, or spray painting or similar.
I got the large one and it is still plenty snug around my lower face. There are ear loops to hold in place, but it stays up pretty well even without that. It's looser around the neck than a gaiter which I find more comfortable. It does extend further down in front much like a tiny bib to help keep sawdust from getting in at the top of your shirt.
It feels soft and appears well made, and comes with its own pouch that you can use to launder in the washing machine. It also comes with a rubber adjustable strap which I assume you can attach to the ear loops and wear behind your head. It looks good and is lightweight. Overall, a good choice.