When wide-open isn't wide enough, the Fetish Fantasy Extreme Spider Gag will get the job done!
This extreme gag consists of a steel ring with four curved metal "legs" attached to the ring. The gag and legs prevent the mouth from closing, leaving your subject's mouth wide open for whatever you wish to put in it.
The diameter of the ring measures 1.5", and the gag connects to a leather strap that buckles in the back and keeps the gag firmly in place. One size fits most.