About three of four small items I've bought from hong kong sellers on ebay were misrepresented or just junk. It cost more to return them than their worth. They get government subsided postal rates, and pay less for international postage than we do for US mail in the USA. This means $$ to return it.
I bought a tripod foot for my 100mm L, and they sent the wrong one. So next time, I bought from a different seller who guaranteed it was the right one. Wrong, it was for the 100mm USM as well.
I also bought a wireless remote release with a 400 ft range, but it worked on a good day out to maybe 6 feet, but more often two feet, just junk.
There are some sellers of Brand name merchandise like Digital Rev that don't have that problem, but in the USA, they are also quite a bit more expensive, and its graymarket with no US warranty.