Garmin DC 50, GPS Dog Transmitter High-sensitivity, top mounted GPS/GLONASS receiver with stainless steel VHF antennas (includes two VHF antennas -18  standard and 22  long-range) Innovative bark detection technology and 9 mile range (depending on terrain) Improved 26 to 54 hours battery life (depending on update rate) with included rechargeable lithium-ion Rescue Mode -prolongs battery life by slowing down the rate at which it updates the Astro 320 Compatible with the Astro 320 handheld only. It does not work with Astro 220 or Alpha handhelds