iM3 Stainless Steel Mouth Gags - set of 3 (5, 8 & 12cm)Unlike other (heavy duty spring loaded) mouth gags that can over extend the temporomandibular joint, the iM3 designed mouth gag has a unique locking system that requires little force to hold the gag at the desired open position inside the animal's mouth. The lightweight gag and spring coupled with the unique locking system reduces the risk of myalgia, neuralgia, and or trauma to the temporomandibular joint. 3 sizes in the pack: 5cm opening. 8cm