SRAM is excited to announce that, starting in January 2012, production of all X9 10-speed and 9-speed trigger shifters (front and rear shifters, all current colors and speeds—2×10, 3×10 and 3×9) will be upgraded, using the same pull lever ball bearing technology used in XX and X0 shifters. The ball bearing replaces a bushing, resulting in a more solid feel, more precise shifting, and overall higher performance.
All new and existing orders will be filled using the upgraded X9 ball bearing shifters. The current X9 shifters will be discontinued. This change results in a product with significantly improved performance and value.
Source: Tyler Morland