Bit gag
From wipipedia.org
A bit gag is based on a horse bit and is often used in pony play. As a tool for silencing someone, it is much less effective than other types of gag. However, the visual impact is as great as (some might say greater than) a ball gag. The risks of wearing a bit gag are much less than a ball gag since it does not obstruct the airway. Bit gags can be fixed in place either by a single strap running behind the back of the head or as part of a head harness. The bit can be made from a variety of materials, rubber, wood, and metal being popular choices.
Bit gags are also valuable tools for humiliation exercises, since they tend to cause the wearer to drool freely.
