The STKR Garage Side Parking Sensor is easy to install and has an adjustable distance motion sensor. Simple mount the Side Parking Sensor to the garage doors track using the supplied universal mount. Safely position your vehicle with the side view mirror as close to the sensor as possible. When your vehicle is in position, press the set button. This is now the warning zone. The sensor will now alert you if you drive your vehicle any closer to the edge of the garage doors opening. An easy to follow green, yellow, red color sequence lets you know if you are safe to proceed, in the warning zone, or if you need to reposition your entry or exit to avoid contact. The red signal light is accompanied by a warning siren to adequately alert the driver to realign their path. Let the STKR Garage Side Parking Sensor guide your entry and exit, protecting your car from unnecessary damage. Battery or USB powered.