Power: 1.5V (AAA) x 2 (battery not included) Product Advantages: BSIDE ZT-E8 Smart socket tester are mainly used to detect polarit of power socker and safety of leakage switch . The super-large color display is left as an excellent user experience for customers. It can quickly and accurately detect the connection status of the socket at the same time. It can intelligently detect the presence of dangerous voltages. It can test the socket voltage and display it on the LCD display. The product has Three plug specifications (EU/US/UK), which can meet the requirements of different countries and regions. Product description: Includes 7 different patterns for you to read:Correct / Ground Open / Neutral Open / Live/NEU Reverse / Live/GRD Reverse / Live Open / Live Ground Reverse Miing Ground. Dangerous voltage warning: Yes. RCD/GFCI Test:Yes. Work voltage:2.6~3.3V. Test voltage range:0.1V~250V/40~1kHz. Work temperature:0 C~40 C. work humidity:20%~75%RH. Stock temperature: -10C~50 C. Stock humidity:20%~80%RH. RCD current:>30mA. GFCI current:>5mA. RCD work voltage:220V20V. GFCI work voltage:110V20V. Battery:2*AAA Battery. Does the package contain batteries:Include battery Package includes: 1* ZT-E8 Socket tester(EU/US/UK Plug) 1* English manual 1* Color box