I'll give these a 4 out of 5, not totally fair, since I am using them for a modified purpose.
They have knobs that allow them to fit yakima rain gutter towers tightly. I have a "Utility Van Rack" that I mounted on my camper, and it required using an angle grinder to remove these knobs.
I think they could get away with a knob on only one side, the rear, and still have a great product.
For the intended purpose, with Yakima towers, these are a 5/5. I just want better versatility.