Borrow Bosch D-tect 120 Digital Wall Scanner

D-TECT120 features Spot Detection technology that can detect objects instantly when placed on a wall, panel or floor. Since the Bosch D-TECT120 never needs calibration, you can focus on the job without worrying about accuracy. Three modes ‒ drywall, universal and concrete ‒ make this the right detector for multiple jobs. Universal mode sees through more material, it sees "anything in anything". This device offers sound and a light to show user when something is detected behind a wall, panel or under flooring.

(Description from boschtools.com)