Compatible Systems: 11-speed Di2 systems only. Insert into the dedicated port on Di2 STI levers such as the ST-6870, ST-9070, ST-R8050, and ST-R9150. SHIMANO SW-R610 Sprinter Switch Di2 Electric. Not Compatible: Cannot be used with levers without a Sprint port, such as the ST-7970 or ST-6770.
eBay