The clamps are designed to be adjustable. It took me a while to figure out how to adjust the pressure of the clamps, but eventually I figured out that you have to open the clamps and then screw in the screw that sets the tightness of the clamping.
The pressure of the clamps depends on how far the screw is in or out of the clamps. There is also a rubber tip at the end of the clamps, and when removed, the clamps definitely have more of a bite to them.
The clamps are held together by a metal chain that is very strongly linked. I think that is the only downfall about the clamps, because the chain is so heavy that it makes the clamps more likely to fall off. (That also depends on how tight or how loose you like your clamps to be).