This Ergonomic Golf Grip Training Aid is Molded with Contoured Indentations & a Finger Cutout to Lock Hands into the Standard Correct Holding Position Automatically. Made of Flexible Wear Resistant Rubber Material, It Fits Most Standard Golf Club Shafts, Usable on Drivers, Irons & Putters for Indoor & Outdoor Practice. It Helps Beginners Eliminate Incorrect Twisting & Weak Grips, Building Consistent Swing Muscle Memory, Lightweight & Reusable for Daily Range Training Sessions.