Shimano Tourney Rear Derailleur RD-TX800 7/8 Speed SGS Direct Mount (Black) Model: Shimano RD-TX800 rear derailleur, suit for 7/8 speed Double Servo design keeps pulley close to sprockets for better shifting Large guide wheel, a whole new innovation for your mountain bike Variable speed boot device - precise and reliable speed We guarantee our products quality, any question in using, we are 100% responsible