BATTERY PACK LIHD 36 V ? 6.2 AHLiHD battery packs for ultimate performance and extremely long application with minimal temperature generationUltra M technology: Intelligent battery management for long-lasting battery packs with a 3 year guaranteePatented ?AIR COOLED? charging technologyPermanent Electronic Single Cell Protection (ESCP) when charging, for particularly long life.Processor-controlled charge and discharge managementCapacity display with almost no self-dischargeCapacity display with almost no self-discharge