This is a used Shimano Dura-Ace RD-7970 Di2 10-speed rear derailleur. The pulley cage stopper pin has been replaced with an aluminum bolt instead of the original part (see photos), but this does not affect functionality.
Wolf Tooth | RoadLink DM - Derailleur Hanger Extender for Shimano Rear Derailleur Road 11 speed | Enable Wide-Range Gearing with MTB Cassettes on Shimano 11 speed road rear derailleurs.
SHIMANO Rear Derailleur 9v SS-RD-R3000 Sora
SHIMANO Rear Derailleur MTB DEORE M5100 1x11V Long Cage 51
SHIMANO Rear Derailleur 8v SS-RD-R2000 Claris
SHIMANO Rear Derailleur MTB DEORE XT M8100 1x12V 45 Teeth Black
Shimano Rear Derailleur Cable Fixing Bolt & Plate - RX812 - Y3GF98020
