DieHard 71219 Battery Charger and Maintainer for $19.99. Order online for in-store pickup at Kmart to lock in the price and save on shipping. Otherwise, shipping is $6.50. Here is a screenshot for your reference. This battery charger/maintainer features a float mode monitoring for 6 and 12 volt batteries, and 2 Amp, 12 volt/4 Amp, 6 volt slow charge with reverse hook-up protection and includes 50-amp battery clamps, 12V accessory plug and permanent ring connectors.