Bought two of these at the original price of $50. Opened one and used it to connect a thunderbolt Lacie 2Big drive. Didn't turn on. Thought the drive was dead, got another drive. Then that was dead. So I swapped cables and voila the new drive worked. So the problem was that one of my 2 cables was dead on arrival (DOA). On insertion, it felt notably more "tough" to insert than the second (good) cable. Of course I didn't know how a thunderbolt cable should feel on insertion since the DOA one was the first I'd ever used.