J L.
From a price to quality perspective, this is a great gag option you want if you want to experiment and aren't sure what to get, the ball itself isn't too big and should fit comfortably in most mouths.
The strap/buckle/locking bit itself is a little tricky to correctly close by yourself, but it is easy once you did it a few times, length wise, just a little more length would allow you to "close" it and them lower it overhead in place, but this is hardly an issue worth complaing about, and depending on the wearer may not even be an issue.
I definitely recommend this gag for other curious first timers.