First Alert SFA275 Parking Alert Sensor

Easily mounts on wall, workbench or shelf in garage; Ultrasonic range-finding technology; Uses 3 different light indicators with alert sound based on range from sensor; On/off switch; Powered by included 120V AC adapter or 9V battery (required); Includes mounting tape; Display unit dim: 7.28H x 2.4W x 1.22D; Sensor dim: 3.23H x 2.4W x 1.46D;