The Lubell Labs Underwater Loudspeaker has remained the most popular underwater speaker in the world since 1968, as it's patented design is significantly louder and clearer than competing designs and products. This unique design (U.S. Patent #3,391,385) utilizes a dual-piston PVC overmolded aluminum enclosure as the sound transducer, offering true pistonic operation and low Q in a compact corrosion-free package. Coupled with a powerful 8-cylinder piezoelectric engine (with efficiencies approaching 60%), no other brand compares!