It’s a horrible moment – the crunch when you reverse a bit too far. Attach this 8H x 6W x 3D cm ultrasonic sensor to the garage wall and it need never happen again! The lights on the wired 18.5H x 6W x 2.5D cm display change to amber then red so you know exactly when to stop. Powered by a 9V battery (included) or your own adaptor it could help you save a fortune on repairs! Please note, adaptor is not included.