The package includes: 4 black detectors (sensors), a buzzer that emits sound signals, a control panel, and a hole saw for drilling holes in the bumper. Installation instructions. The buzzer can operate in three sound modes: high, low, and completely muted. The mode can be changed with a switch on the housing. A parking sensor is a device that assists with parking and reversing the car. It works on the principle of sonar - it emits ultrasonic waves that, upon reflection from an obstacle, allow for the determination of the distance between the car and the obstacle. When reversing, the device accurately detects obstacles in the vehicle's path and warns the driver with an acoustic signal. Full specifications: Operating range/sensitivity 0-2.5 m. Power supply 12 V. Operating frequency 40 kHz. Operating temperature -30 °C to +70 °C. Mounting diameter 22 mm.