On the end of the pen are two dials with a (+) and a (-) at either end. The innermost ring adjusts the temperature setting. By rocking the ring in the direction of the (+) or (-) you will increase or decrease the temperature by increments of 5 degrees. When changing the temperature setting, the new target temperature will temporarily be reflected on the LCD screen. It will then display whatever setting you are currently operating on as it moves towards the target temperature. The LED will turn blue when the target temperature is reached.