The Cervelo SP24 is a D-shaped proprietary seatpost that fits certain models of Cervelo bikes, including the 2020 - present Caledonia and the 2017 - present R5. FEATURES: Cervelo carbon seatpost for Caledonia and R5 Proprietary D-shape matches the aerodynamics properties of the frame Includes seatpost head assembly SPECS: Offset: 0mm Length: 370mm Material: UD Carbon