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. Race Face Narrow/Wide Single Chain Ring Features Narrow 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. Sizes: 30, 32, 34, 36, 38, 104 BCD (4 bolt). Weights: 37-57g (36T: 50g).