HP Series Putter The HP Series of putters features five different head styles ranging from traditional to modern high-MOI designs. Every style incorporates a soft-feeling face insert. The insert contains micro-grooves that reduce skidding off the face. HP Series putters also include a jumbo grip. The grip helps prevent golfers' wrists from breaking down making it easier to create a pure and fluid putting stroke. In addition, the jumbo grip reduces grip pressure and minimizes club head rotation for a softer touch and more pure putting stroke.