The genuine Colnago internal seatpost clamp is engineered to the exact tolerances of the V4RS, C68, C68 Gravel, and G4X frames, matching the internal diameter of the seat tube with the precision only an original factory component can offer. Sized at 29.0 x 31.8 mm, it seats securely inside the frame, distributing clamping pressure evenly around the seatpost while keeping the frame's internal routing and finish completely untouched.