The UW30 underwater speaker is equipped with a waterproof, three-conductor, 50-foot cable. It features eight-ohm impedance, and is available in pool blue. Underwater speakers are required by the American Athletic Union for synchronized swimming events and instructions in Olympic pools. They are also ideal for water ballets or similar water shows and resort or private pools. Built for installation in both fresh and salt water pools, the UW30 can even be safely installed in ocean environments. The speaker is designed for permanent installation and completely submerged operation. Problems such as corrosion and electrolysis damage are completely eliminated by plastic construction. The 12.7-ounce ceramic magnet and state-of-the-art voice-coil construction ensure high-fidelity response with low distortion throughout the power range. One speaker is recommended for pools up to 30 feet x 30 feet, or two speakers for pools up to 30 feet x 60 feet.