little nub on iSkin gen2

[bingle]

I've got a 2nd generation 10G iPod with an asphalt colored iSkin case on it (the "Protect" case?). Anyway, the case has a little nub near the top on the left with a metal insert through it. What is the purpose of this nub/insert?

On a related note, are there any belt clips like the Lajo TwistClip that will fit this iSkin?

Thanks!

[HiRes]

I've heard of someone using Lajo's TwistClip on their iSkin, and I'm considering buying one. I'm still not sure though.