The LS mouthpiece incorporates two different hardnesses of silicone molded into one mouthpiece. Different thicknesses of bites and perfect positioning of hollow semispheres to ensure incredible comfort and fit for extremely low jaw fatigue without gum irritation, even during very long dives. Lateral “channels” give the flexibility for a better fit into the particular morphology of the mouth. The spheres at the top and bottom stimulate the lips, relaxing them while making them assume the ideal position. LS mouthpiece fits on all Mares regulators.