RP-SMA

sma connector in wikipedia

RP-SMA connectors are widely used by Wi-Fi equipment manufacturers to comply with specific local
regulations {Section 15.203 Antenna requirement}, e.g. the FCC, 
which were intended to make it difficult for consumers to connect antennas with gain 
and thereby breach compliance. 
However, RP-SMA equipped antennas are now widely available

File:200px-RPSMA.jpg female RP-SMA.......... File:200px-SMA connector.jpg male SMA