acr TerraFix 406 GPS I/O NH PLB Includes internal GPS and a connector for external NMEA 0183 position input 406 MHz Satellite Search and Rescue transmitter, 121.5 MHz Homing Beacon transmitter Size: 1.74 x 5.71 x 3.03 in.; Weight: 12 oz. w/o holster; floats 24 hour transmit time 5 year battery shelf life