A capo (10) for use with a stringed instrument comprises a top arm (12), lower arm (16) and a lever arm (24). The top arm (12) is adapted to extend across a fingerboard of the instrument above the strings (4), and a side arm is connected and extending at an angle to the top arm and arranged to extend generally laterally of the neck (2) of the instrument. The lower arm (18) has one end pivotally attached to the side arm (16) at a lower arm pivot (20) and is adapted to abut against the back of the neck of the instrument when in a closed position. The lever arm has one end pivotally attached to the side arm (16) at a pivot (26) spaced from the lower arm pivot (20). The capo further includes an adjuster mechanism (28, 334) that extends and projects an adjustable amount from the lever arm (24) and has an end tip (32) which bears against the lower arm (24).