The Race Face Narrow/Wide Single Chainring comes 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 Chainring 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.