Standard Horizon's flagship VHF Radio, the Quantum, offers DSC class D calling/ receiving and scrambler capability to create a versatile on-board communication system. These radios meet requirements for commercial ITU class D with a separate channel 70 receiver which allows DSC calls to be received even when listening to traffic on marine VHF channels. Larger rotary knobs allow easier channel, volume, and squelch control. A large 3" x 1.5" LCD display makes this VHF a pleasure to use. The 4" internal speaker provides louder and clearer audio, and the PA and Fog Horn system have been boosted to 30 watts. You can also connect up to 2 RAM+ mics giving you the capability of two and three-way communication. When connected to your GPS, the large backlit screen will display Lat/Lon, speed over ground, and course over ground. The channel changing mic has Standard's exclusive Clear Voice noise canceling technology to allow crystal clear broadcast over noisy engines and wind. The Quantum is submersible and also features NOAA Weather Channel and alert, preset key for instant recall of two favorite channels, and one-button access to channels 9 and 16. The Quantum GX5500S adds an alphanumeric keypad for quick access to most often used functions, input of DSC names, and direct entry of channels. 3.5"H x 9.1"W x 6"D. Three-year warranty. Note: MMSI# must be applied to enable DSC function.