NOTE 1.This package does not include batteries. Due to rules of China customs, parcels must not include batteries, otherwise it will not get through the custom. 2.Remember to install 2 battery in both transimitter and sender (the small box). 2.If you need Ruian instruction, please contact us. Description of Automotive Digital Car Battery Tester, Click the below page. DESCRIPTION of EM415PRO Automotive Wire Wand This instrument is designed to identify and trace wires or cables without damaging the insulation. You can also use it to check short circuit and loacting open circuit and so on. There are a Sender and a Receiver included in the instrument. FUNCTION 1.6-42 V Ready: for use in the new generation of vehicles with mixed or single 6-42 Volt systems 2.Operates on DC voltages from 6 to 42 volts 3.7" flexible probe allows reaching wires in congested places 4.Transmitter and Receiver LEDs show open or short circuit condition 5.Adjustable sensitivity for all tracing situations 6.No wire piercing required, non-contact technology!