Chauvin Arnoux VX0003 BioTest LF Electric Field Tester. Detect the level of elecromagnetic radiation given off from electrical equipment with this magnetic field tester!. Featuring a built-in internal sensor, the VX0003 uses a dual LED scale to show the level of detected EMF radiation. It's suitable for use with a wide variety of electrical equipment, including computers, printers and fax machines, lighting and HV power lines, transformers, railways and other applications. The VX0003 has two measurement modes. Using the traditional mode, the user connects the tester to earth with the field referenced against earth. Using the representative mode, there's no cables required and the user's presence is taken into account when measuring to maintain accuracy.