Sram rival black 10 speed rear mech supercharged shifting with bulletproof precision sacrifice nothingnot durability dependability or performance nothing the new rival rear derailleur matches srams exact actuation with tried and true competition proven design and construction exact actuation delivers even gear changes over the entire shifting range via a precise 3mm adjustment from gear to gear maximized for 10 speed systems the rivals design is descended from srams legendary mtb rea