SparkFun BLE Nano!

The BLE Nano from RedBearLab is the smallest Bluetooth 4.1 Low Energy (BLE) development board in the market and with the included MK20 USB in this kit you’ll be able to deploy firmware to BLE Nano even easier. At each BLE Nano’s core is a Nordic nRF51822, an ARM Cortex-M0 SoC plus BLE capable of running at 16MHz with ultra low power consumption. The RedBearLab BLE Nano also supports numerous different wireless devices running iOS 7/8, Android 4.3 or higher, and Windows Phone 8.1.