Ubiquiti MiniStation 2,4 GHz.

World's Smallest 802.11 AP Development Platform
Full Linux SDK available

Even smaller than a credit card and consuming less than 4W, the MiniStation can be used for a variety of applications where size/power is critical.

Processor Specs                             Atheros MIPS 4KC, 180MHz
Memory Information                       16MB SDRAM, 4MB Flash
Networking Interface                       1 X 10/100 BASE-TX (Cat. 5, RJ-45) Ethernet Interface
Frequencies                                   2412-2462 MHz.
RF Connector                                 1xMMCX, 1x integrated PCB printed antenna
Wireless Approvals                          FCC Part 15.247, IC RS210
RoHS Compliance                           YES
Max Power Consumption                  5 Watts
Power Method                                 Passive Power over Ethernet (pairs 4,5+; 7,8 return)
Operating Temperature                    -20C to +70C
Software                                         Ubiquiti AirOS