NEW: Series 91 "The Duke" putter. In honor of Ken Duke's recent win at the Shaw Charity Classic on the PGA Tour Champions, the company is releasing a putter inspired by Duke's model. It features the same slight half-mallet shape of the putter Duke used to hole the birdie that clinched his first win on the senior circuit. The Series 91 uses 50 grams of tungsten in the heel and toe to build a moment of inertia over 5,000 grams-centimeters squared, distinctly high for the size of the head. As well, the design incorporates the company's trademark low-balance point weighting. The components include a lightweight (44 grams) graphite putter shaft and grips that weight as little as 29 grams. Together, that saved weight up top means the vast majority of the overall mass of the putter is concentrated toward the head. This is designed to allow the player to develop a more natural control of the face angle to bring it to square at impact. The Series 91 head is made of 303 stainless steel. $350, lengths from 32 to 36 inches.