I am offering the top-tier rear derailleur from Shimano's GRX gravel groupset. It is in absolutely mint condition (see detailed photos, e.g., image 117668.jpg) with only minimal signs of use. It is in perfect working order; the jockey wheels run buttery smooth and the spring has full tension.
The rear derailleur features the integrated Shadow Plus chain stabilizer (clutch), which can be engaged via the grey lever to effectively prevent chain slap and chain drops on rough terrain.

Technical data & details:
Model: Shimano GRX RD-RX810
Speeds: 11-speed
Compatibility: Perfect for 2x11-speed drive...