Working process: Signals when approaching an obstacle at different distances. A long interval beep sound at approximately 0.50.8 m. A short interval beep sound at approximately 0.30.5 m. A continuous beep sound at approximately 00.3 m. Installation: Simple and concealed installation. The sensor antenna is fully installed inside the bumper without drilling. Maintenance-free; no cleaning or washing required. Compatible with most cars, trucks, RVs, and minivans. Peel-and-stick antenna foil tape sensor for vehicle bumpers. Connects to reverse lamp (12 Volts DC). High-output piezo buzzer provides audible alerts. Color: Black Material: Plastic Package Contents: 1 x Control box 1 x Buzzer 1 x Antenna 1 x Ties Note: The package includes only the items listed above. Other items are not included. Light reflection and differences in display screens may cause slight variations in color between the product image and the actual item. Measurement error allowance is +/- 13 cm.