The M12™ NRG pack comes with the M12 B4 4.0 Ah battery and the C12 C M12™ charger, providing extended runtime and dependable performance for M12™ cordless tools. The 4.0 Ah battery allows longer operation between charges, while the C12 C charger ensures quick and efficient recharging. This pack is ideal for demanding applications and keeps MILWAUKEE® M12™ tools ready for use.