1.99% of the cars' alarm systems are compatible with this product. The working voltage is 7V-40V. 2.Human voice instruction makes the system easy to operate without a instructor. 3.Self control It respects personal privacy and sets the owner at rest as there is 24 hours' watching, timely emergency treatment in the center, with no incorrect alarm. 4.The concealed installing way prevents cars from destruction, with no destroy of the inner look of cars. 5.Industrial GSM module and GPS module assure the stability and reliability of the car in the complicated environment. 6.Wireless car telephone There two ways to listen to the telephone call, picking it by hand or automatically. Hi-fi voice instruction gives you a face-to-face conversation. 7.Selective fittings: remote resume trunk, automatic riser 8.Location If you adopt the Global System for Mobile communication, this system will help you to locate the car.