This compact 18V charger gets the user power ready in a hurry. The Bosch GAL18V-40 Lithium-ion charger can fully charge a spent CORE18V 4.0 Ah Lithium-ion battery in approximately one hour, and it is compatible with all Bosch 18V Lithium-ion batteries. This means that users are ready to get back to work with little downtime. It is engineered with regulated 80/20 dual-mode charging for fast and safe charging. It features charging indicator lights showing when the battery is fast charging, charging in long-life mode or finished charging. The error indicator will alert the user if charging is interrupted due to temperature and/or battery failures.