The Shimano 1x 10 Expander Sprocket Kit from One Up Components is an incredibly easy-to-fit pair of sprockets that replace two of the stock cogs to give you 90 percent of the benefit of a 1X11 system but at 10 percent of the cost. The larger cog fits behind most 11-36T cassettes, displacing one from the main cluster. The 16T sprocket provides even more cassette progression for smoother cadence & enhanced shifting. These cogs feature 12 upshift optimized points & uses the original 28/32/36T steel sprockets for maximum durability. Available in Black or Green.