The Shimano 105 HG-X CN-HG600 11-Speed SIL-TEC Bicycle Chain features an asymmetrical design for improved shifting. SIL-TEC is SHIMANO's new ultra-low friction surface treatment. SIL-TEC products run smoother and wear longer in all conditions.Original Shimano parts guarantees that all components work perfectly for optimum performance and maximum safety and longevity.