mPCIe Combo + Dual-band Wi-Fi/Bluetooth 4.0
Combo Power Up!
"Hook up immediate extra connectivity to the ROG motherboard and say so long to physical limitations. The unique Combo attaches to the motherboard near the rear I/O , and comes with one mSATA port supporting Intel® Smart Response Technology hybrid storage acceleration with compatible mSATA SSDs, and a dual band 2.4/5 GHz Wi-Fi 802.11 a/b/g/n and Bluetooth v4.0 card bundled into its mini PCI Express 2.0/USB 2.0 combo port on the opposite side. This way, you can connect extra devices without taking up valuable space on the motherboard, and get the best of both worlds: for better connectivity and expandability without sacrificing essential feature"
That's straight off the Asus Maximus V Formula website.
It's one of the "bigger" features to the board. They advertise it like crazy, so it has to have 5 if all of the asus website are claiming it does.