Shimano GRX, with its gravel specific ergonomics, optimized gearing options, rugged reliability, and quiet and stable drivetrain, sets itself apart from the rest of the component world The RX820 series offers premium performance at an incredible value, with thoughtful ergonomic designs and gravel-centric gearing for all manners of unpaved adventures. Features: - Silent and secure rear shifting on rough terrain - Adjustable chain stabilizer prevents chain slap and drops - SHIMANO SHADOW RD+ - Smooth and reliable shifting on mixed surfaces - ON/OFF stabilizer switch matches terrain - Maximum front chainring difference: 17T - Top sprocket: Max. 11T/Min. 11T - Low sprocket: Max. 36T/Min. 34T - Total capacity: 42T - Low profile Shadow Plus design 12-speed rear derailleur for fast and precise shifting performance - Shadow Plus uses a chain stabilising switch that when on will reduce chain bounce in rough terrain maintaining more stable drive and shifting - High tolerance cold forged aluminium link plates and body construction is extremely light and durable - Compatible with 12-speed Hyperglide plus chains - Wide gear ratio compatible up to 11-36T - For use with double chainset