The Ping Scottsdale TR Anser 2 putter features a variable-depth-groove insert for a smooth roll and improved distance control. The grooves are deepest in the sweet spot (middle) and get gradually shallower as you go towards the perimeter of the insert. This technology allows for maximum energy transfer and counter acts the loss of energy on off-center hits. It is designed for the golfer who has a slight arc putting stroke as opposed to a straight back and straight through putting stroke.