Model Number: P1581 Key Specifications/Special Features: The module includes a siren as well as three in-builtsensorsMillivolt sensor: this sensor constantly monitors the batteryvoltage of the car and is triggered by small voltage drops causedby the doors or trunk being openedShock sensor: alarm is triggered when the vehicle is bumped,disturbed or towedpressure sensor: alarm is triggered when the air pressurechanged by doors being openedSensor, transmitterRemote controllerMain unit