SRAM Quarq Riken Power Meter BB30, BCD 110, 50/34T, 170mm. Unidirectional carbon fiber arms and aluminum chainring spider provide excellent strength-to-weight. X-Glide tooth profiles and shift assist pins enable quick and reliable front shifting. Please message with any/all questions!Also, don't forget to SAVE US as a Sell er! This item is in the category "Sporting Goods\Cycling\Bicycle Electronics\Power Meters". The seller is "bikesaresofun" and is located in this country: US. This item can be shipped to United States.