Keep your canine companion found with the Garmin DC 30 dog-collar transmitter, and leave the bushwhacking to your dog Transmitter relays dogs position every 5, 10 or 30 seconds to the Astro 220 GPS receiver, sold separately. DC 30 transmitter collar is weighted to maintain position of transmitter above dogs back. Flexible antenna on DC 30 withstands rugged use in brush. Up to 7 mi. line-of-sight range, depending on terrain. DC 30 transmitter offers 17 to 36 hours based on position pinpointing frequency on rechargeable lithium ion battery pack includes AC wall adapter and DC vehicle charger. Waterproof construction keeps unit functioning meets IEC 60529 lPX7 standards submerge 1m for 30 min..