How to replace the slide potentiometer?

Hi Guys,

I bought my Arduino Esplora from RadioShack when I went to U.S. But it seems the slide potentiometer is broken by my mistake. I can’t find anything about that potentiometer model or brand. Any idea where I can find the same one for replacement?

I really love my Esplora, I don’t want it to be sick.

Thanks,
Tony