This OSPW X system for Shimano GRX RX820 2×12-speed rear derailleurs is built for gravel and cross disciplines and meets the needs for durability, low friction and longevity. The four spring tension settings allow customised setup based on ride conditions, and the handbuilt OSPW System offers custom molded carbon fiber cage for lightweight and durability. CeramicSpeed OSPW Systems reduces friction 35-40% over stock pulley configuration.