- For SRAM cassettes that use an 11 or 12 tooth cog in the 1st position - 10sp X-Glide: aluminum construction for a 11 tooth first position cog *(also for use on XG-999 9sp cassette and replacement for discontinued PG 7-9sp / OG-1090 alloy lockrings) - 10sp Open/Power-Glide: aluminum construction (1070 level), or black steel (1050 level) - 9sp PowerGlide-II style: 11t red aluminum (970 DH level), silver aluminum (970 level), or black steel (950 level)