Nordic Semiconductor Bluetooth, WiFi USB 2.0 WiFi Adapter

The Nordic Semiconductor nRF51 Dongle is designed for Bluetooth Smart, ANT and other 2.4GHz wireless applications. The development platform is based on the nRF51 series of wireless System-on-Chips and supports both the nRF51822 and nRF51422 devices. The Dongle incorporates the nRF51422 SoC and supports the Nordic Software Development tool-chain using Keil, IAR and GCC. The ARM mbed cloud-based IDE and tool-chain is also supported.
The dongle can also be set up as a Bluetooth Smart packet sniffer using Nordic nRF Sniffer software. The Master Emulator firmware and Master Control Panel Software enable setting up of a peer device that can be used to test the connection of your application. The nRF51 dongle supports all Nordic SoftDevices.

nRF51422 ANT/Bluetooth Smart RF Transceiver SoC
USB PCB connector
6 x GPIO pads
Boot/Reset pushbutton
User RGB LED
PCB Antenna
SEGGER J-Link OB Debugger
Virtual COM port interface through interface MCU
Supports mbed IDE

A packet sniffer can be used to look at everything that goes between two Bluetooth Low Energy devices over the air. Its a good tool for debugging or learning about Bluetooth applications.