The double layer structure prevents the glass from coming off even in the event of a sudden situation. Previously known as the “inner ring structure” has been securing the glass with the inner ring alone. However, “LANZE” uses a double-layer construction system that holds the inner ring with the center part and secures the center part with the frame and screws (interlocking system RAT.P). Therefore, the glass is not easy to fall off even in the event of an emergency, and this safety design is attracted to the attention of divers. We’ve repeatedly tested and improved the safety of the inner ring, center parts, and screw fastening. LANZE is difficult for water to enter in. The secret is it! Dear Divers have ever experienced “laughing in water and getting water into the mask” or “When you put the mouthpiece there was a gap in the skirt part”. This way, the most easy to get water into the mask is around the mouth and nose. The “LANZE” “LEAKLESS SYSTEM” is the “LANZE” that fits the muscles of your facial muscles and the smoothest lines.