Warning about non-Apple bands, especially the bargains from China
Short Version: If you have a band adapter like the one in the attached picture, those little screws can come loose and the band comes apart.
My wife has three inexpensive but decent bands she got on ebay from China. I'd read stores of the screws in the cheap band adapters working loose so I warned her to be aware of it. After only a few days she told noticed that the adapter was getting loose. I checked and sure enough the tiny screws (see attached) were very loose, nearly to the point that it was about to come apart.
So I checked all three bands. One of the bands had some sort of "threadlocker" on the screw threads but the other two had none. I added some blue Locktite to all the screw threads (4 per band).
I don't know if the blue Locktite is best, I'm open to suggestions. They make a "red" version but it's darn near permanent.
Another thing, the screws seem to be either a very tiny phillips or a non-typical-Apple sized Pentalobe (like the attached pic). I was able to make a partially worn out Torx work but I've ordered a nice Pentalobe screwdriver set on ebay so I'll be covered for the next time.