Jeff Catalanowrote a review of Yakima Control Tower - Set of 4 on October 12, 2016
Familiarity: I've put it through the wringer
I got these and Landing Pads #1 to set up with round bars on my truck camper that has Yakima tracks. They keep the bars more than secure enough for a roof box full of skis and camping gear, and a kayak. I'm a little bummed that the Control Towers don't come with SKS locks, but installing locks is incredibly easy (and recommended so your stuff doesn't disappear on you). Overall solid purchase for the foundation of your rack setup.