Such carriers are well made, the adjustment knobs are convenient and accessible. A BTR screw added to security in the event of incorrect operation (inadvertent removal from the wheel for ex.) Thereby preventing the moving parts will dissociate and your falls pregnant! For this purpose also extra security was added: a small steel cable connects the 2 moving parts (the product is therefore seriously).
In short for the price, you will be satisfied with these supports.
From + I can tell you they are really strong because I have round one side to fit correctly on a rounded enclosure and it was not easy !! (The sheet is very strong).