The FSA SL-K carbon tandem cranks feature an asymmetrical modular compact 2x11-speed spider, 30mm spindle, and tons of adjustability.Asymmetrical 110 A.B.S BCD achieves 4 chainlines (44,47,50,53). English BB included. 104 BCD timing spider. 653 grams. Hollow carbon arms with UD carbon finish are incredibly strong and lightweight. Item Specifications: Color, Black, Rings, 38, Number of Chainrings, Single, Crank Length (mm), 175, Crank Intended Use, Tandem, BB Included, English, Pedal Spindle, 9/16", Spindle Interface Type, 392 EVO, Chainring BCD, 104, Defined Color, Black,.