This exclusive Toolstop set contains 2 x Milwaukee M18 B4 4.0Ah Batteries and the M12-M18 FC Fast Charger The Milwaukee M18 B4 4.0Ah batteries deliver up to 2x more run time, up to 20% more power and up to 2x more battery life compared to other Lithium-Ion technologies. REDLITHIUM protection with REDLINK digital overload protection prevents users from damaging their cordless power tool investment in abusive situations. This set also comes with the M12-M18 FC Fast Charger which charges all M18, M14 and M12 REDLITHIUM battery packs. It will fully re-charge the included 4.0Ah batteries in just 52 minutes. M18 B4 Features: Delivers up to 2x more run time, up to 20% more power and up to 2x more battery life compared with other Lithium-Ion technologies and/or with previous Milwaukee battery technology REDLITHIUM protection with REDLINK digital overload protection to prevent users from damaging their cordless power tool investment in abusive situations Individual cell monitoring ensures optimal charge and discharge for maximum life Durable metal frame battery construction with shock responsive separators preventing pack failure from excessive vibrations or drops Water protection routes water away from the electronics & out of the battery pack Can be used in extreme temperatures down to -20 °C without compromising on runtime and battery life On-board battery fuel gauge helps the user to maximise his battery run-time efficiency M12-M18 FC Features: Recharges all M18, M14 and M12 REDLITHIUM battery packs Recharges in sequence - first in, first to charge resulting in less time needed to manage charging cycles M12 REDLITHIUM 4.0 Ah battery packs recharge in 52 mins or less M18 B4 Specification: Battery pack capacity: 4.0Ah Voltage: 18V Battery type: Li-ion Charge time M12-18 FC charger: 52 mins M12-M18 FC Specification: Charge type: Sequential Charging ports: 1 x M12, 1 x M18 Power source: AC System: M12, M14, M18