The class D (digital selective calling) capability enables you to transmit vital emergency information including your boats identification, position and time the distress call was sent using NMEA data from your GPS. The Ray 54 also offers popular VHF features such as DSC position request and DSC phone directory. Four line GPS data display. All channel scanning. 1 or 25 watt output power. 16 plus key quickly gets to channel 16 or preset priority channel. Tri-watch scans working channel, priority channel and weather channel. Waterproof to IPX7. On-mic controls for ease of use. Large backlit LCD display. External speaker jack. Rotary channel/programming knob with push to enter. Dimensions: 2.9"H x 6.5"W x 6.47"D. 3 year warranty.