Yes C-Groove Callie-F Putter. Introduced in the UK in August 2006, the Callie-F is a traditionally styled cavity back putter formed from one piece of forged manganese-bronze. The C-Grooves are precision cut into the face to reveal Golden Colour Grooves. All but the grooves are then oxidized to provide a non-glare finish to the head. YES Golf have worked diligently at perfecting the style, look, and weighting of the new line of C-GROOVE Putters whilst maintaining the technology that has professionals and amateurs talking about YES Golf. Developed by Putting legend, HAROLD SWASH, the C-GROOVE Putter has precision machined patented concentric grooves that grip the ball and get it rolling sooner and truer than any other putter on the market. Yes C-Groove Putters are the only putters to reduce skid and impart true forward roll on the ball. Even under adverse conditions, the C-Groove Putter will roll the ball more accurately - and with a softer more responsive feel.