Bimodule Synchronous Test -- EMF meters can test both radiations in electric field and magnetic field at the same time for precise . Sound & Light Alarm -- Radiation detectors will assess the test and it will automatically alarm when it's over the safe value. Alarm : Electric: 40V/m; Magnetic: 0.4T Ecofriendly & Fashion -- USB rechargeable. Portable and simple design makes digital radiation testers are easy to carry around and do field measurement. Data-Locking & Backlight -- Press one botton to lock the data and clear display with blue bakclight allow you to read results. Accuracy: 1V/m for Electric, 0.01T for Magnetic. Measure Temperature -- Swicthable temperature units ( and ). 0C-50C Colour: black Material: ABS plastic Size: about 133 x 60 x 25mm Package Contents: 1 x electromagnetic radiation detector 1 x USB cable 1 x English manual Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.