Notice the 1-bolt seat clamp. The single bolt goes laterally through the clamp. It's simple and easy to adjust, but those do not hold the saddle from tilting down as well as 2-bolt (front/back) seatposts do (e.g. Thomson). My Felt TK1 had that system and the seat kept tilting. I wasn't the only one who had that problem.

Also, I don't think anyone has solved the carbon seat post slipping problem 100%. Google: Aero Seatpost Slipping, and you will see what I mean.