If a typical sonar fish-finder isn’t cool enough for you, try the Humminbird RF35 watch. The watch is wirelessly connected to the Advanced Remote Sonar Sensor. The RF35 watch has a 1.25″ (diagonal) gray-scale LCD display. It has a backlight and is waterproof. The sonar sensor can “see” to a depth of 120 feet. The Humminbird RF35 is $79.99 at the Humminbird online store.