YAD Shimano Altus Rear Derailleur RD-M280 7/8 Speed Long Cage Direct Mount Mountain Bike Shimano Altus Rear Derailleur RD-M280 7 or 8 speed compatible, 13T pulleys Double Servo design keeps pulley close to sprockets for better shifting It is designed to bolt onto the rear frame, comes with a bolt to secure it to the bike Works well with 7/8 speed mountain bike and very easy to install