Shimano Ultegra CS-R8100 Cassette Lock Ring & Washer Description: This Shimano Ultegra CS-R8100 Cassette Lock Ring & Washer works to replace or repair Cassette Lock Ring and Spacer found onboard Ultegra CS-R8100 Cassettes, along with select other cassettes. Features: Replacement Cassette Lock Ring and Spacer for Shimano Ultegra CS-R8100 Cassettes See compatibility tab for full list of compatible cassettes Specifications: Material: Alloy Color: Black