Product details:

Tipping the scales at a mere 222 grams, the FSA SL-K Carbon SB20 drops precious grams from your trusty steed while optimizing stiffness and ride quality. FSA's unidirectional carbon provides ample stiffness and vibration damping at a weight that's not much heavier than FSA's top-shelf posts. It's available with a 20 millimeter offset in either 27. 2 or 31. 6-millimeter diameters, at a length of 350 millimeters. Both available posts come with a polymer Di2 battery holder for keeping up with future drivetrain standards.