It's one of the most popular sex toys. There are lots of manufacturers. It's a good toy for girls to get unlimited foreplay, but mostly it's for the thrill of being teased and controlled, and having your manhood taken away so you're forced into the girl's role. The fun ends when you orgasm, but you can stay horny and excited for days in a cage.
Also, OP do this one: (well, I've done my rolls, and hit pillory, not release)