Features: 1. When reversing gear is engaged,the system will start working automatically 2. 2-digital digit with 3 colors 7 light bands LED display the distance of the obstacle from behind 3.Stage-by-stage sound alarm to avoid colliding 4. Display type: LED digital display 5. Sensor type: drilling type or stick-on type 6. 2 / 3 / 4 sensors are available 7. Versatile sensor colors are available to fit the car body color Specifications: 1. Working Voltage: 9-27v 2. input: 2.5w ( max) 3. Beeper: 70-105dB 4. Working temperature: -40C - + 80C 5. Frequency : 40KHZ 6. Best Detection distance: 0.5m - 1.5m