STX Golf Pro Fit Putter Customizing Kit Customizing Kit Includes: 1 red insert, 1 green insert, STX adjustment tool and STX storage pouch The red insert provides medium feel for slower greens and adds 3" of distance when compared to the black insert The green inserts provides firm feel for very slow greens and adds 6" of distance when compared to the black insert. Increase in distance based on a 15' putt