Review (4/5): Decently durable; easy to use; could be a bit longer
These are reasonably durable mask holder bands. The "fingers" that hold the mask straps are thin, but I didn't experience any tearing even when tugging on them a lot harder than they would be exposed to in normal use. The fingers are widely spaced and can deal with flat-style elastic bands without a problem.
My only quibble is that they are a bit too short in length. While using them does increase mask comfort around my ears, they would be better if they were about an inch or so longer.
Not ideal, but a helpful aid to increase long-term mask wearing comfort especially with masks that have short ear loops.