For people who is happy just to hunt, then the Garmin Astro DC 40 dog collar tracking the right thing for you because it's your retriever, and helps to get your game without wondering where the devil was after Fido long wait for him to return. This second-generation device offers many improvements, including built a durable one inch strap, a GPS receiver into the main part of the band, and a charging socket designed better. The Astro 220 receiver can be up to 10 different dog collars, where he will receive all updates length necklaces five, ten, 30 or 120 seconds of rechargeable batteries.