 On the other side of the mouthpiece, excess and exhaled air escaped from a simple rubber "ducks bill" valve.The diver's nose was pinched by a pair of spring clamps ("pince nez") to prevent ingress of water, and his eyes were protected by small goggles with rubber surrounds.Le Prieur was impressed by the simplicity of the Fernez equipment and the freedom it allowed the diver, and he immediately conceived an idea to make it free of the tube to the surface pump by using Michelin cylinders as the air supply.