The Makita BL1021B 12V 2.0 Ah Battery Pack is a lithium-ion battery that provides longer run time and lower self-discharge than traditional batteries. It features an integrated LED battery charge level indicator, so you can easily see how much power is left. The battery is also compact and lightweight, making it easy to carry and use. It is compatible with a wide range of Makita 12V tools, so you can use it for a variety of tasks.