The Extech MD10 Non-Contact Magnet Detector with Built-In Flashlight shows the presence of a magnetic
field, including AC, DC, and permanent magnets without contact. These fields are easily indicated by the
blue LED light that turns on when it has detected one. The Extech MD-10 also has a flashlight built into
the device to light dim areas. The detector is useful in testing audio speakers, troubleshooting solenoid
valves in pneumatic and hydraulic control equipment, and testing relays with coils and electrically
controlled solenoid valves in vehicles and machinery.