The Shimano RD - R8000 Rear Derailleur Ultegra 11 - speed Medium Cage Double is a top - notch component suitable for 28 - 34t gears. It offers smooth shifting and reliable performance for a great cycling experience.

To use this rear derailleur, first make sure it's properly installed on your bike. When shifting gears, gently use your shifter to move the chain to the desired gear. Remember to shift smoothly to avoid chain skipping. As for maintenance, regularly clean the derailleur with a soft cloth to remove dirt and grime. Check the cables for any signs of wear and replace them if needed. Also, keep the moving parts lubricated to ensure smooth operation. If you notice any strange noises or difficulty in shifting, it's a good idea to have it checked by a professional.