Bought this product for occasional use in transporting my bike to the shop when I know I'm leaving it with them for a service. (I have a small boot but car has a towball). All other tow ball carriers where very expensive and according to the fitting info, the ones that strap to your bootlid won't work on my car due to it's rubbish construction!
On receipt the item did not fit properly and flapped about on the tow ball like the one in the picture of the guy with the Merc.
Basically the cross brace was on the highest holes (adjustible to tighten or slacken fit with the highest being the tightest) and was still loose. I think this is probably down to poor "Quality Checking" by the manufacturer and I'm sure if I'd contacted the seller and returned the item they would have replaced with another, which based on other reviews would have been fine.
To be honest I didn't have the time for that and having only spent [] quid and being fairly practical I quickly and easily modified the one I got by drilling further "adjustment" holes and now it's nice and snug.
In summary, a decent bit of kit for little money if you get one that's been made right or you're handy with a drill and some spanners.