The SRAM Apex rear derailleur is available in both a short and medium cage. The short cage can handle up to a 28 tooth rear cog while the medium cage can handle up to a 32 tooth rear cog for a truly wide-range drivetrain. It features SRAM's Exact Actuation for precise even gear changes throughout the shifting range. Exact Actuation delivers and even 3mm adjustment from gear to gear. SRAM's road derailleurs descended from their legendary MTB rear derailleurs so they can take a lot of hard use.