Connect stackmat with computer?

[chickenfly34]

Where can i buy the black one in this video? i had to try in Office Depot, Office Max. BUt they did not have. An adapter with 3,5mm (on the hole) and 2,5mm (on the other side)
http://www.youtube.com/watch?v=gE0OoUhP6pU

Thanks you!

 

[VP7]

Go to Radio Shack.