Quickly press the button 3 times to change the voltage setting. The LED light flashes (3) times to reflect the current setting. It is best to start any new Pod at the Low setting. Low (2.7V) is indicated by a Red light. Medium (3.4V) is indicated by a Green light. High (4.3V) is indicated by a Blue light. - (Use High setting with caution.) -- 350mAh Rechargeable Variable Voltage Pod System -- Safety: Do not leave your battery at a temperature that is too hot. This will cause the battery to drain and short. Leave your battery charging for the required time of 30 minutes to one hour. Leaving it charging overnight can cause a battery shortage. Make sure your pods are clear of debris before placing them into the battery.