Race Face Single Rings - Now with performance enhancing chain retention technology. Burly enough for DH Racers and Dirt Jumpers, yet light enough for XC / singlespeed. Single Rings are machined from 7075 aluminum and tested in some of the most punishing riding terrain - Built to last.FeaturesNarrow Wide tooth profiling ensures ultimate chain retention.,Stiff 4mm plate thickness and I-beam construction transfer loads without flexing.,7075-T6 aluminum, aerospace grade strength.,Reversible laser etched graphics.,Compatible for 9, 10 and 11 speed..SpecificationSizes: 30, 32, 34, 36, 38, 104 BCD (4 bolt).,Weights: 37-57g (36T: 50g)..