The FLEXVOLT? 20 V/60 V MAX* 12 Ah battery provides up to 8X runtime in 20 V MAX* and delivers ultimate power in 60 V MAX* and 120 V MAX* cordless tools. It changes voltage when you go from 20 V MAX* to 60 V MAX* tools. Lithium-ion technology delivers performance in the same size as our 9 Ah battery, so it is more powerful in as compact a package as possible. It also includes a built-in LED fuel gauge for instant charge status and is compatible with 20 V MAX* tools and chargers.