GPS Pet Dog Tracker Collar Locator - Work for iPhone - Free Collar by ROUNDSQUARE BUY MICRO SIM CARD - You need to buy a MICRO SIM CARD to use the device & for pay the service company for the GPS, text and other services they provided. ACCURATE LOCATION - Outdoor locating by GPS, the location is within 16 Yard from the dog. Indoor locating by LBS, the location is about 55 Yard to 550 Yard. GPS+LBS Dual Location for pet. Find Them Quickly if They Get Lost.The ROUNDSQUARE GPS Pet Tracker lets you set your pet's home zone and notifies you if they wander off using its award winning GPS location tracking system. GLOBAL COVERAGE - ROUNDSQUARE uses cellular and GPS technology to pinpoint your dog's location all over the world.But pls make sure your sim card provides 850/900/1800/1900 GPS frequency band. TEXT & EMAIL ALERTS - On-demand notifications via app, text and email alerts when your pet gets out. WATERPROOF - IP65 Waterproof Level to avoid splash water when pet is playing.