Momentus  Training Grip Ideal for Overlap, Interlock, or 10-finger gripping styles. The core size fits .580 - .600 cores of both steel and graphite shafts. The Momentus Training Grip was designed by a PGA TOUR professional and features texturized locations for a quality feel. The molded right hand V placement aims directly at the right shoulder while the left hand thumb placement allows for either a short or long left thumb