Aero BTS PRO - cupThe PRO cup unit on its own for riders who already have an Aero BTS Carbon Saddle Clamp and want to add the PRO's 900 ml storage tray and tighter bottle shell. 900 ml of integrated storage 100 ml more than the standard cup PRO shell geometry hugs the bottles for a tighter aero profile Fits all Aero BTS Carbon Saddle Clamps Holds 2 1000 ml bottles in the wide V formation Saddle clamp not included. The Aero BTS Carbon Saddle Clamp is sold separately.