It operates under the WiFi A & B mode and is relatively low power (~ 70 mW). The fact that it is not running G/N is not an issue since very little data is actually transferred. A newer version running the G protocol is available in the same foot print, but the power consumption is nearly 4 fold while the cost is about twice.
The modules come in two flavors, one with a built in antenna and one with a jack for an external connection (pictured). The built in antenna works really well and is nearly perfectly omnidirectional, however if you put it in a metal enclosure, you will want the external antenna.
It s a semi-smart module, in that is does all the WiFi protocol and encryption (WEP,WPA, WPA2) on board, but it does not contain the TCPI/IP stack and Servers on board like some modules slated for 8-bit controllers such as those used on Arduinos do. This allows for a much broader API compared to the simple and slow UART interface found on those so called smart WiFi modules.
The radio is permanently attached to the underside of the main board by means of a 10 pin soldered connection.
I have been pretty happy with these modules, the only thing I wish they had is a means of reading the signal strength/quality of the connection from the board. You will have to consult your wireless router to see what the incoming signal strength from the device is.