Extralite ExtraBolt 15 jockey wheels replacement bearing, fit Extrabolt 15.0-15.1-15.2. It's an high quality sealed low friction bearing, 12x8x3.5 mm size. Please remember that each jockey wheel require 2 bearings.
Extralite UltraPulley 13-13, ultralight rear derailleur 13T jockey wheels. Fullly Delrin CNC made, double 2RS sealed ceramic bearings. Only 13.8 gr. weight for the pair, Great smoothness, quietness and shifting precision. Compatibile with Shimano MTB 12 speed rear derailleurs. 100% Made in Italy.