The SiSeries putters feature precision cast 303 stainless steel heads with soft thermo plastic urethane (TPU) face inserts and SeeMore's patented RifleScope Technology (RST) alignment system, for a true reference point for perfect alignment and set up on every putt. SiSeries putters feature an expanded sweet spot with enhanced perimeter weighting, and a softer feel and slighter less rebound for those preferring the performance of a tour level elastomer insert. SiSeries putters offer a range of options in terms of shape and design to meet every golfer's needs in a line that offers great value and performance.