Dual-Pull Cable Routing ( Convenient Dual-Pull feature allows derailleur to be set up for top or bottom cable routing according to cable anchor position). Compatible with 34.9mm & 31.8mm frame Tube Sizes. Reinforced Chain Guide (Special chain guide cross section offers high strength and rigidity for improved shifting response). Mega-9 Compatibility (Designed specifically for use with super-narrow 9-speed chains). Top-low Max. Capacity: 22T. Top-middle Min. Capacity: 12T. Top Gear Teeth: 44T. Mount Type Band Material: aluminum/painted. Outer Link: aluminium/painted. Inner Link: aluminum/painted. Chain Cage: steel/chrome plated.