Portable, durable and water resistant GPS / GSM / GPRS tracker for vehicle tracking, equipment / assets monitoring. Users can install TR-151 on vehicles or assets for tracking. Using GPRS over the GSM network its location (longitude/latitude), speed, altitude and heading are sent to our internet based application. Users can track the location of their vehicles or assets. TR-151 is designed to equip with high capacity of Li-ion battery for long operation time. There is one SOS button on the TR-151 for emergency help. It is very easy to install or hide. TR-151 is ideal application for vehicle tracking and equipment / assets monitoring.