Working closely with Cervelo and their wind tunnel testing results, Xlab developed an aerodynamic single rear system specific to Ritchey clamp seat posts with a 10 mm horizontal rear hole. The Delta Sonic fits snug into the seat post providing a sturdy non-sway bottle mount for fast and safe access to your bottle. The Delta Sonic rod can slide along the seat post for the best customized fit for you. XLAB recommends a 1" insertion minimum into the seatpost.
Xlab has found these bikes to be compatible with the Delta Sonic: Cervelo P5 & 2013 P3, Scott Plasma, Kestrel 4000, Fuji D6 & Norcom, BH Aero. Includes Delta Sonic Rod, Xlab Gorilla XT Cage plus hardware and installation instructions. If the saddle is in the rearward position, you may want to look at the DELTA SONIC XL.