Tooluxe 40517L Car Battery & Alternator Tester for 12V Cigarette Lighter Socket | LED Indicators Battery meter monitor easily plugs into standard 12V cigarette lighter port Labelled LED lights indicate power and charge levels of alternator and battery that is easy to check Diagnose problems with battery or alternator yourself without a technician or mechanic and save time Automotive voltmeter can help avoid car malfunctions due to low battery Battery voltage meter for cigarette lighter receptacles is compact and can be stored in glove box