The M18 & M12 rapid charger charges packs up to 40% faster， reducing downtime and maximizing productivity. The charger accepts all M18 and M12 batteries， providing an upgrade for both systems. Featuring REDLINK Intelligence， it communicates directly with the battery to monitor cell voltage， temperature， and charge status to optimize the performance and extend the life of the pack. Sequential charging - automatically charges the second inserted pack once the first pack is fully charged. As an added level of communication， the charger indicates when the battery reaches an 80% charge.