Bluetooth SMART low energy module which allows new generation devices the ability to connect to a Gadgeteer main board via Bluetooth 4.0 LE.
Socket type: U
Devices with BLE hardware include:
HTC One, One X+, Droid DNA
iPhone 4S, iPhone 5, iPad (3rd gen & 4th gen), iPad Mini and others
Nokia Lumia 820 and 920
Samsung Galaxy SIII, Galaxy S4, Note II
Microsoft Surface Pro / RT
Blackberry Z10  and Q10
I have personally tested with a iPhone 4S and a USB dongle on Windows 8.1
I believe for Android you need 4.2 firmware (S4 has that)
Win8 Phones don't have software support yet, but isn't far away....