Features:
A professional tester for identifying the polarity of field fastly and safely.
Pen type tester, and portable.
button operation, easy to use.
The north and south polarity can be distinguished by the two (red = N , green = S ).
Comes with a sturdy tool .
It can be used for the determination and identification of permanent and electromagnet poles, magnetization polarity check, and coil test.

Specifications:
Material: ABS
Sensitivity: ±5mT (50Gs)
Display: 2 (red = N , green = S )
Service : -20~80℃
Storage : -40~150℃
: 2 * 1.5V AAA (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
1 * Manual (English)