Gain a cool and confident putting stroke with a new PING Serene Putter. The Serene Putter features variable-groove-depth technology. The grooves are deepest in the center, and get gradually shallower as you get to the perimeter giving your putts predictable distance and accurate results. The PING Serene Putters have an insert made of 6061-T6 aluminum giving the club a traditional steel face. That, coupled with a well-balanced geometry, gives the putter an increased level of forgiveness. The PING Serene Putters come in four models.