Abstract: A exercising and conditioning device is used in the chord hand of people who play a guitar or similar stringed instruments. The device has a body with an upper surface containing a longitudinal groove. At least one string is tensioned within the groove below the upper surface so that, when the body is held in a hand, all the tips of fingers of that hand may extend into the groove to depress the string. Depressing the string builds callus pads on the ends of the fingers and strengthens muscles used to depress the strings. Placing the string within the groove assists in guiding the fingers to the best position on the string.