Milwaukee MX FUEL™ CP203 3.0Ah Battery 2.7kg. MX FUEL™ REDLITHIUM™ batteries leverage the best-performing and highest-quality lithium-ion technology. Delivering AC power in a compact and portable battery pack, allowing users to work in areas where power cords struggle to reach. ONE-KEY™ tool tracking & security offers a free of charge cloud-based tracking network and inventory management platform for your tools.