Around the clock protection for your pet. Uses global positioning systems tracking and two-way wireless technology. Notifies you when your dog leaves his boundry; alerts via text message, email or telephone voice message. Track your pet via the website or have a customer care specialist stay on the phone, offering directions to your pet. Walk mode lets you temporarily remove pet from boundry. Fits neck sizes 10 and up. Recommended for dogs 30 pounds and up. Risk-free 30-day trial, lifetime limited warranty. Unit measure:3.75 x 2.5 x 1.25 inches. Unit weight: 4.2 ounces. Includes: gps locator, adjustable collar, 4 rechargeable batteries, recharger, and operating guide.