The FSA spider system uses a three-armed spider and 86mm bolt circle diameter to deliver an extremely stiff and lightweight crank set. The SL-K Compact PF30 has unidirectional carbon fiber arms with a strength-enhancing alloy spine. With a very deep cross-section to the cranks, the spider arms can be very short for stiffness – one of the three mounts is behind the crank arm itself. White Logo OEM Package PF30 Bottom Bracket included