The color code dot system for the Ping Eye 2, as well as other Ping products, is a method of custom-fitting clubs to a golfer based on two measurements: the height of the person and the distance from the player's wrists to the ground when standing naturally. A chart of the 12 color codes can be found at the Ping.com website, by clicking on Fitting Process under the Fitting drop down menu.
The base color for a Ping club is a black dot, with hosels at a standard angle. A hosel that is more upright benefits golfers with shorter arms, whose wrists are farther from the ground, while a hosel that is flatter is better for golfers whose wrists are closer to the ground. Clubs that are too upright for a player can cause him to draw, hook or pull the ball, and those that are too flat may make him fade, slice or push the ball.
A blue dot club has a hosel that is 0.75 degrees more upright than a black dot club. Hosels become an additional 0.75 degree more upright at each color level, stepping up through yellow, green, white, silver and maroon, which is 4.5 degrees more upright than black. Clubs becoming flatter than the base black dot club step down in 0.75 degree increments, moving through red, purple, orange, brown and gold, which is 3.75 degrees flatter than black.