Sourcingbay Waterproof Mini GPS Tracker with SOS Button, SMS Alerts, Android and Web Application For child/the elder/Pets / Vehicle Black The tracker uses the existing Global System for Mobile Communications (GSM)/general packet radio service (GPRS) network and Global Positioning System (GPS) satellites to locate and monitor the tracker. The tracker can be located or monitored by Short Message Service (SMS), the internet, and by mobile app for both iOS and Android. Auto track/Voice surveillance/Geo-Fence/Speed alert/SOS button/SOS call mode/Low battery alert etc. Adroid Download address www.zg666gps.com ;iphone Download address: app store TKSTAR GPS (you can use it for free) Please Note: This GPS trackers need to use a Sim card for 850/900/1800/1900MHZ, not support 3G,4G sim card. The package no include sim card,customers need to get it from your own country by yourself