Although the vast majority of fish finders operate at the 50/200 kHz, there are many other frequencies available that are utilized almost exclusively in commercial applications. These include 15 kHz, 28 kHz, 33 kHz, 38 kHz, 40 kHz, 88 kHz and 107 kHz. The following is a list of Furuno transducers that operate within these frequencies. Commercial transducers such as these are generally mounted in tanks or sea chests that are custom built into the ships hull. Some transducers are designed exclusively for use with Net Sounders, while others are used by commercial fishermen or other high seas vessels that require the most reliable depth sounders available.