Whitehead gag
From Wipipedia
A Whitehead gag, also called a mouth spreader gag or a dental open mouth gag, is a device to hold the mouth open. The device is similar to a Jennings gag, the main difference being the two ratchets in front of the gag to hold the mouth open. The image shows a Whitehead gag modified for BDSM use, with a strap added to help hold the gag in place.
For issues concerning the use of this type of gag, read the article on the Jennings gag.
