Guitar Capos

What exactly is a guitar capo, and why do you need it? Guitar capos clamp down around the fingerboard at a certain fret, in order to shorten the length of the vibration of the strings. Basically, your guitar capo acts like a movable and adjustable nut - you can move it anywhere up the guitar neck and impact your guitar's tuning. Capos will bind all (or some) strings simultaneously and effectively create a brand new nut. With a guitar capo, all open strings will play in higher tones than they do when the capo's not on the fingerboard. That's why it's so important to mount the capo immediately behind the desired fret, to ensure that the strings are correctly pressed.