When you installed BSM into your lovely car, no matter it's day time, night time or even in the snow, you can be alerted whenever there is a moving object pop into the rear of the vehicle, with the aid of LED lighting on , blinking, buzzer sound so that the driver can be cautious when lane changing to avoid the possibility of side crash accident. When you get ready to get off, open the door, if someone moves behind, it will also give an accurate alarm. Detection Range Accuracy : ±3cm About installation: Please Read The Instructions Carefully Before Installation!!! Note: Transition: 1cm=10mm=0.39inch No retail package. Please allow 1-3mm error due to manual measurement.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1Set Universal Blind Spot Monitoring System. All items will be checked before packing. All items are new and of high quality. The item "Car Rear View Blind Spot Monitoring BSM Ultrasonic Sensor Radar Detection System" is in sale since Thursday, February 28, 2019. This item is in the category "eBay Motors\Parts & Accessories\Car & Truck Parts\Safety & Security\Other Safety & Security". The seller is "2014lwjfy2014" and is located in Cerritos, California. This item can be shipped to United States.