I've tried 3 other devices so far, and have been having trouble finding something that fits.
This device fits perfectly, when I'm totally soft it's snug, and it's just small enough to stop me getting hard, but not so small I can't try!
The shaft of the device extends back past the ring meaning I can't escape. I can feel it right down to my base when soft.
The padlock is held in place on top, so no rattling. It would be relatively safe to break it off too, if the keys were lost!
The plastic is smooth, and doesn't chafe like my other plastic toys. A couple of slightly rough spots where it needed polishing down.
All in all, this is by far my favourite cage so far, and also by far my cheapest. Fit seems to be everything!