The Shimano RD-6700 Pulley Set is for use with Shimano Ultegra 10-speed RD-6700 rear derailleurs. It is a genuine Shimano replacement part.
It is also compatible with the following Shimano rear derailleurs: RD-6700, 6600, 6500, M805, M772, M750, M801, M771, M751, M806, M770, M760, C910, M810, M761, and M800 rear derailleurs.