I say again, if you want robust get the
9.solutions clamps I linked. They are totally solid; more so than Manfrotto.
To OP: I feel very strongly that clamps are one area where you do
not want to save money buying a cheap clone. Consider that you are trusting this clamp to securely hold what is usually the most expensive part of your rig, your mics. There may be additional stresses placed on the mic if using an extension arm. Cheapie clamps may be made with lower-quality parts that are much more likely to fail.
Would you rather pay a little bit more for a high-quality clamp, or replace your mics after they come crashing down?