OTC 3131AGM MinuteMan Plus Multi-Application Electrical System Tester with Cart MinuteMan Plus saves you hours when you're testing batteries starters alternators regulators and charging systems. Special AGM test options for accurately diagnosing AGM and spiral six-pack style batteries Tests starters in seconds with no need to disable ignition Checks the charging system at high rpms and at idle and stores the data Displays cranking volts and amps and indicates either good or bad starter