Box components Box Two Prime 9 X-Wide 9 speed black rear derailleur

Prime 9 Technology is a counter-intuitive philosophy based on the less is more theory - it embraces range without adding complexity. Intended for use with Box Components` Prime 9 speed group not compatible with other 11-50 cassettes. Same functions as the Box One Prime 9 derailleur with more affordable materials. Glass fiber/nylon composite steel aluminum alloy. Tri-Pack limited slip clutch. Forged inner and outer cage. Pivot-Tech cable stay. Precision sealed bushing pulleys