Track your dog at a range of up to 9 miles with updates as frequent as 2.5 seconds when used with a compatible handheld (sold separately) Rugged yet slim design is universally sized to fit large and small breeds User-replaceable flex band Get extended battery life with dynamic tracking based on your dog’s movement Identify your dog, even in the dark, with a large, easy-to-see multicolor LED; colors include yellow, magenta, cyan, white, green, red or blue Get automatic updates when the Alpha T 20 dog collar is charging and connected to your network with Wi-Fi technology Pairs with Garmin dog tracking handhelds such as Alpha and Pro 550 Plus (sold separately) Batteries are user-replaceable and easy to change; when using dynamic tracking, a standard pack lasts up to 68 hours, and an upgraded expanded battery pack lasts up to 136 hours