Shimano Sora RD-R3000-SS Rear Derailleur - 9 Speed | Short Cage Brake Levers This is a significant improvement

This is a significant improvement over previous Di2 battery designs that required removing the battery for every charge -- with the BT-DN300

The steel backing plate provides solid pad-to-piston contact for consistent bite and reliable bedding

It is ammonia free and runs as a one-step product with no separate activation

or rattling

maintaining consistent inflation across the contact patch without the irregularities that affect undersized or cheaply made tubes in this format

Shimano Sora RD-R3000-SS Rear Derailleur - 9 Speed | Short Cage Brake Levers This is a significant improvementWhat Is the Shimano Sora RD R3000 SS Best Used For? The Shimano Sora RD R3000 SS is a 9 speed road rear derailleur in short cage configuration, built for road bikes running close ratio cassettes up to 32t. Aluminum bracket body, fluoric coated link bushings for reduced friction and smooth cable pull, and a stainless steel B axle deliver lightweight, durable performance for entry level and recreational road riding. DYNAMIC INTEGRATED ROUTING cable