Cervelo does a great job supporting their customers with small parts. Though many S-Series frame designs use an internal wedge system now, several historical designs employ a traditional style (if not shaped), seatpost. If you have an S-Series frame with an aero seatpost and accompanying NACA shaped seatpost clamp, it may be here.

Cervelo uses forged aluminum for the their clamps, which limits sharp edges that my scratch your frame. A stainless steel Hex bolt secures the clamp to the seat tube extension. Though not listed on the collar, the max torque specification is 4Nm. We recommend using carbon friction past on the post itself, and always use a torque wrench when fastening the bolt.