Features:Prerequisite: a car should be equipped with original alarm system and central door lock of negative trigger.You can still use the original remote controller to contol the system.Multi-level security arming & high reliability and quality.Can be used in different types of cars except for Benz， BMW and Audi.Basic Functions include:Arm/disarmTrigger alarmMemorize triggered alarmStatus memoryAuto rearmingEmergency disarmingAutomatic central door lockDoor-opened warning (under the disarming state)The Main Control Unit with Jumper， function is selectable.(Removing the jumper's cover means function on， otherwise means off)Jumper features: Function Jumper off Jumper onJumper 1 Automatic central door lock Without WithJumper 2 Siren sound Without WithJumper 3 Auto-rearming Without WithJumper 4 Door-opened warning Without With1. When you choose "Without" in the function of "siren sound"， the siren will keep silent under the states of the arming， disarming， shock alarm and Memorize triggered alarm， but when the door alarm， bonnet is triggered as well as ignition alarm， the siren will sound.2. When program the above features， the system needs to be powered off by taking the whole socket out of main unit at first， after 5 seconds， put the jumper on or take the jumper off to select the feature. Then Power the system on， the selected feature would be functional.Specifications:Main unit working voltage: 12VTotal weight: 573g / 1.3LbsPackage including:1 * Main Control Unit1 * Shock Sensor1 * Siren1 * LED Light1 * Flameout Relay1 * Set of Wiring Harness1 * Instruction Manual