SRAM RED E1 172x46/33 DUB NoBB CARBONUltra light hollow carbon fiber crankarms 29 g lighter than the previous generation One piece 2x chainring results in a lighter weight, stiffer, more durable crankset X Range gearing technology gives you more range and a smoother gear progression, so youre always in the right gear 50 37T, 48 35T and 46 33T chainring combos available DUB bottom bracket adds durability and simplicity Can be upgraded to a power meter