This bundle includes 2 DJI Mavic Air batteries and 2 ME Martian Elite safety bag.The battery adopts the latest technologies to ensure that the flight control system is able to obtain accurate battery level. This allows it to calculate remaining flight times more accurately. It also gives pilots a full understanding of the overall battery status, including real-time battery cell status, circle number, temperature and more, and all in the DJI GO app. As well as monitoring the battery status during flight, the BMS also has overcharge and over discharge protection, reducing the likelihood of battery damage.. When not in use for extended periods of time, DJI Intelligent Flight Battery automatically discharges to 50% charge, keeping it at an optimum charge level for extended battery life. When flying in cold temperatures, the BMS will activate low-temperature protection and will control power output according to the temperature. This ensures the battery can provide adequate propulsion without damage from the cold.