FMJ is correct, it is a Trans X anti theft skewer, I use them when out and about, and put the QR's back in when I go off road.
There is a threaded hole down the centre the special tool screws into to keep the pentagonal key in place so the wheels can be spun off, they work pretty well, not bad at all for the cost, but a pain if you lose the key.
The special tool comes with the skewers, a set in silver or black for £11 free p+p on fleabay