Description: A professional tester for quickly and safely identifying magnetic field polarity. Pen-type magnetic tester, mini and portable. One-button operation, easy to use. North and south polarity can be distinguished by the two signal lights (red = N-pole, green = S-pole). Comes with a robust plastic tool case. Can be used for determining and identifying permanent and electromagnetic poles, checking magnetization polarity, and coil testing. Specifications: Material: ABS Sensitivity: 5mT (50Gs) Display: 2 LED lights (red = N-pole, green = S-pole) Operating temperature: -20~80℃ Storage temperature: -40~150℃ Power supply: 2 * 1.5V AAA battery (NOT included) Item size: 154 * 27 * 24mm / 6.06 * 1.06 * 0.94in Item weight: 64g / 2.27oz Package weight: 263g / 9.30oz Package size: 22 * 10.5 * 5.7cm / 8.66 * 4.13 * 2.24in Packing List: 1 * Tester 1 * Storage Case 1 * Manual (English)