WiFi is the wireless networking IEEE standard IEEE 802.11 and it's used across the globe. Many different versions have been named (half of the alphabet has been used already to name these) and an incredible amount of improvements have been proposed since the introduction of the standard in 1997. Our WiFi shield supports the use of several versions: Wireless B, Wireless G and Wireless N. This is stated on the outside of the WiFi module. These versions differ in their transfer rate, frequency range and reach. The transfer rate can depend on the amount of antennas. Wireless N uses MIMO (multiple in, multiple out) and therefore the WiFi module will have multiple antennas. Only one antenna is visible, so the other one or two will be built-in.