Using your Fender Original Guitar Tuner is a breeze. First, insert the included 3V (CR2032) lithium battery. Then, clamp the tuner onto the headstock of your guitar or other stringed instrument. You can adjust the 360° swivel to get the best viewing angle for the LCD screen. Play a string, and the tuner will use its vibration - based system to show you if the string is in tune. Make sure to keep the tuner away from extreme heat or cold as it can affect the performance. When not in use, store it in a dry place. If the battery runs out, simply replace it with a new CR2032 battery.