Shimano GRX Rear Derailleur RDRX820SET 12-speed
 
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