The Milwaukee M12 NRG-201 Energy Kit, contains the following:

1 x 12 Volt M12 C12C Li-Ion Charger, with a compact and lightweight design that gives you more runtime and power, enabling you to work longer after charging. Cutting edge electronics eliminate memory effect, the battery can be charged at any time without reducing the charging capacity. Constant fade free power throughout the discharge cycle.

REDLITHIUM-ION™ 2.0Ah battery packs recharge in 40 minutes or less.

1 x 12 Volt M12 B2 REDLITHIUM-ION™ Battery Pack, fitted with sophisticated electronics (REDLINK™ Intelligence) and overload protection which prevents the user from damaging their cordless power tool investment in abusive situations. They have a temperature Management System which keeps the battery in ideal temperature range to provide maximum life.