This compact 18 V charger gets the user power ready in a hurry. The Bosch GAL18V-40 Lithium-Ion charger can fully charge a spent CORE18 V 4.0 Ah Lithium-Ion battery in approximately 1 hr and it is compatible with all Bosch 18 V 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 or battery failures.