These Anesthesia Masks were designed with smaller animals in mind. They have a simple cylindrical shape with a rubber diaphragm. A small slit is cut in the diaphragm to accommodate the animal’s snout or beak. The opposite end tapers down to a standard press fitting port measuring 15.3 mm OD x 11.9 mm ID. These Masks can be used with bain circuits, non-rebreathing systems, or ‘Y’ pieces. Includes 1 diaphragm.