What are the main differences between these two headphone models?

I just LOVE the sound quality found in Dr. Dre headphones, and I’m thinking about getting a pair. The problem is, I don’t know why one costs a great deal less than the other. Could you help me?

Here’s the newer one: http://store.apple.com/us/product/TS232LL/A#overview

And here’s the more inexpensive one: http://store.apple.com/us/product/TX669LL/A