This is one of the best car theft prevention and vehicle protection system available today. With convenient SMS ability, full-range of alarm functions including gas to engine cut off, and the latest in GPS tracking technology, the G204 GPS Car Tracker is the ultimate safety device for your car, van, truck, or even the entire vehicle fleet. Track on Demand - Replies with a TXT message of current latitude, longitude, speed, and time, as well as an Internet map link to your cellphone to show you exactly where the GPS tracker/your vehicle is. Geo-fencing control - When the vehicle moves in/out the preset scope, it will send an SMS alarm to the authorized phone numbers. Movement and Speed Alert: The tracker can warm you with SMS message when the vehicle starts to move from a stationary status, or when the vehicle is moving faster than a preset speed. Stop the Engine: You can send an SMS message to the tracker to cut off the gas and battery power, so the engine will remain in an immobilized state until your remove the alarm status. GPRS: With a GPRS enabled SIM card, you can monitor real-time movement of your vehicle with the supplied software on your computer. So how does the GPS Car Tracker work? The unit is powered by automotive battery, and should be installed inside a vehicle . It runs on the latest GPS SiRF III chip-set, a sophisticated GPS microchip embedded into the heart of the tracker which continually reads its own location from low orbiting global satellites and then utilizes the GSM/GPRS infrastructure operated by your cellular network provider to transmit its current location to you. All you need to do is insert a working SIM card, it even has Quad-band Connectivity so it works anywhere in the world. The GPS Car Tracker makes no sound at all, so you are fully aware of what is happening to your car, but the inside driver and passenger don't know that their activity and locations are been constantly reported.