It's a Ritchey Clamp system. Call your local Fuji dealer and they can order one for you.

anyone know how this clamp comes together I bought a d6 and the parts were in a plastic bag... cant figure out how it comes together

Visit your local shop and they can assist you. Always best to have them work on your bike and use a torque wrench.

actually looked up the richie clamp online.. but the only way I could install it is I had to superglue the clamp pieces to the rubber pad.. otherwize it kept falling apart when I tried to attach it.
been riding and racing for 45 yrs I got the tools just lack the knowledge... attaching a seat to this post was a nightmare

They are very finicky. Did you figure it out?