So you have an Electric Imp (or plan on buying one), what's next? Well you're going to need a breakout for it, here's where the Electric Imp Shield comes in. This shield gives you to the interface to adapt an Arduino-compatible board to a WiFi enabled Cortex-M3 core development module.
The RN-USB-X is a Class 1 Bluetooth adapter that solves the problem plaguing complicated and error-filled standard Bluetooth dongles. With power Class 1 not only do you get solid wireless communication but 100 meters of transmission distance as well!