Leather Wrapped Ring Gag
This style of ring gag is somewhat old-fashioned; it’s the sort of thing you used to see a lot in sex shops next to the cheap vinyl whips. Better designs for open-mouth gags are everywhere these days. But these are simple, and they work:
I found this photo in an old Usenet download directory.
Elsewhere on Bondage Blog:
I must admit we still have one of these that is a good number of years old, but it still works and shows little sign’s of wear.