Bondhus 67037 13pc Stubby Double Ball End L Wrenches with ProGuard Finish Keyed Chuck USB outlet to power and Spark Plug Socket USB outlet to power and charge small electronics or AGM batteries Also tests discharged batteries and detects bad cells Applies a true 40 amp load during testing to simulate real world operating conditions and provide more accurate test results Tests 6V and 12V batteries rated between 4AH 50AH Stores the last 50 tests in memory The RC 300 enables the user to blue print known good batteries of different types sizes to drive improved testing accuracy The unit will store up to 40 different blue printed battery types The user can also set customized pass fail settings based on their preferred profile Test results include: battery's measured amp hour (AH) capacity Length Type: Extra Long MaxTorque Ball End delivers 50% more torque than conventional ball ends