When purchasing NASA pins, look for the embossing on the back:

Expedition 23
NASA
ABEmblem.com

to make sure you are getting the NASA authorized version of the pin.

Expedition 23 begins with the Soyuz TMA-16 undocking in March 2010. Three new crew members will arrive shortly thereafter on Soyuz TMA-18.

Expedition 23 crew members from the left are Russian cosmonaut Mikhail Kornienko, NASA astronaut Tracy Caldwell Dyson, Russian cosmonaut Alexander Skvortsov, all flight engineers; Russian cosmonaut Oleg Kotov, commander; NASA astronaut T.J. Creamer and Japan Aerospace Exploration Agency (JAXA) astronaut Soichi Noguchi, both flight engineers. Image credit: NASA