Interesting comment about the C100. I have one bought cheap off ebay, and the temperature reading is several degrees off. It seems to get worse as the unit is powered for a while. I guess it is usable, but I wouldn't rely too much on it.
The Chinese economy seems to work through chains of agents who pass on increasingly dodgy cheap imitations. They don't seem to have any conscience when it comes to selling dodgy kit, it is just about getting a sale, and buyer beware!