I originally bought this about 3 years ago (not from Amazon) but this is a great piece of kit!
This item basically makes your mounting solutions much more versatile and you can clamp it to practically anything (as long as it fits inside the clamp!)
It seems to be made from heavy duty plastic and I personally have cranked the pressure or the clamp to as much as I could and it just doesn't break. It's nice also that it has rubber ends to the clamp so it not only allows for more grip but also means that it won't mark anything your pounting it to.
I originally bought this to use with my Sony Z5 HDV camera in order to attach it to the handle so I could combine it with a RODE NTG2 COURT SHOTGUN MIC. FANTOMES ET BATTERIE by fixing it to the handle. IT worked a treat! And it seems capable of holding a fair bit of weight.
I now use this clamp along side my Go Pro along with a GoPro Tripod Mount
so I can attach my Go Pro to various things without any worries of it falling off as I know it will just stay there!
All in all - this is a great piece of kit if you need a versatile mounting solution! Definite 5 Star!