Rechargeable Cold-Resistant Battery: Engineered for all climates, our batteries guarantee consistent performance in temperatures as low as -20°C (-4°F). Withstand the cold and capture every moment with confidence. Charge three batteries simultaneously: You can charge three batteries at the same time. Simply place them all in the case and connect via the USB-C cable. Easy to Know Your Battery Status: Red light is flashing: Battery level<20%; Solid red light: 20%