Boasting the highest inertia of any PING putter, the Udrainium Series putters greatly reduce twisting, keeping putts on line and in the hole. The five Doc^TM models, each with crisp, symmetrical lines for improved alignment, have very low centers of gravity (CGs) for reduced skidding and a truer roll.  Fully machined from high-grade aluminum, these models feature precision lines and weight placement that expands perimeter weighting to new levels. Their semicircle shape positions the majority of weight on the extreme perimeter and far away from the center of gravity to create an extremely high moment of inertia.