The Magnet Stick is an instrument for testing the presence of magnetic fields. By simply holding the tip of the instrument near the test area, it indicates a magnetic field by glowing. The test lamp responds to all kinds of magnetic fields, from alternating current to direct current and permanent magnets. (Sensitivity 300 gauss 0,3 mT) General Features: Powerful red light in the tip to indicate the presence of a magnetic field. Easy to use. Solenoid valves in pneumatic and hydraulic control equipment can easily be tested. Test relays with coils and electrically controlled solenoid valves in all types of vehicles and machines. Test solenoid valves when servicing oil burners. A test magnet is located under the cap. By removing it and holding it in front of the tip, the function can be tested.