Gas anesthesia mask is installed over the incisor bar, with the cone opening toward the open U
Animal (rat or mouse) is installed by placing its teeth over the incisor bar, and sliding the adaptor forward until the cone is snug about the animal's nose, thereby substituting for the nose clamp
Teeth and cone provide a snug, stable hold Anesthetic gas flows in the tubing connector, past the animal's nose, and out the other side
Spent gas may be routed to recycling, exhaust or gas analysis instruments.