
This is a fairly well designed device. I used it to make sure my wife's car battery was really dead. It reports battery voltage and can indicate if the alternator is working properly. Just don't rely on the instructions, some of the worst I've come across. The little booklet was written by someone who had only a cursory knowledge of English. Once you understand what a tester is supposed to do, just try it and you'll quickly understand how to use the switch settings and what it's telling you. Then read the instructions.

Vgate ICar Pro Bluetooth 3.0 OBD2 Code Reader | Scan Tool For Torque Android To Check Engine Light & Car Faults
19 Review

Autel AP200H OBD2 Scanner Dongle - Wireless Bluetooth Code Reader with Health Status Reports - Diagnostic Tool for Engine, Transmission, ABS, SRS - OLS/BMS Resets - All Vehicles (Android/iOS)
11 Review

Upgrade Your Car Diagnostics With 16 Pin OBD2 Extension Cable Splitter - Male To Dual Female Y Cable - 50CM
17 Review

MUCAR CDL20 OBD2 Scanner - Check Engine Code Reader And Diagnostic Scan Tool For All OBD II Protocol Cars Since 1996, With O2 Sensor, EVAP System, And Smog Test Functions
23 Review