This training aid is used to improve posture, keep connection of the arms with the body. It enforces correct posture. The upper body, arms and shoulders turn together as one unit with less emphasis on the hands and arms. It promotes a compact golf swing by keeping the arms close to the body to prevent “flying elbows.” This is a size Small (chest size 34”-37”). For golfers of all skill levels, men and women, left or right handed. Directions to put it on are on the packaging (worn over your golf shirt).