Features Compact and easy to useIndicate battery charging conditionCheck charging circuit of 12V batteries including sealed acid and maintenance free typeSpecification Size 46 x 102 x 16mmWeight 73 gFunction charger check alternator check 12V battery check cranking check Operating Environment temperature 0C 40CRelative humidity 75 Storage Environment temperature 10C 50Crelative humidity 85 Size 102 x 46 x 16mmOperation Instructions For Charger CheckConnect the Battery Tester to the battery terminals Red Positive BlackNegativeWhen the red light against Charger Check lights charging is completedFor Alternator CheckConnect the Battery Tester to the battery terminals Red Positive BlackNegativeAccelelerate your engine to 2000 CPMWhen the red light against Alternator Check lights the charging circuit is okFor Battery CheckConnect the Battery Tester to the battery terminals Red Positive BlackNegativeIf the red light doesnt react check the connection of the clips to the batteryThe red lights will indicate the approximate percantage of charge in the battery An accurate indication of a batterys state of charge will only be possibile i