Yes, but at the very end of the same page you can read this:
The MCE OptiBay™ Drive Do-It-Yourself Upgrade is compatible with the first-generation and Unibody 17-inch, 15-inch, and 13-inch MacBook Pro, the first-generation and Unibody 13-inch MacBook, the 17-inch, 15-inch, and 12-inch Apple PowerBook G4, and the Mac mini.
System Requirements:First-generation or Unibody MacBook Pro (13-inch, 15-inch or 17-inch) or MacBook (13-inch) running Mac OS 10.4.x or later. PowerBook G4 (12-inch Aluminum, 15-inch Aluminum or Titanium, or 17-inch Aluminum) running Mac OS 9, Mac OS 10.2, Mac OS 10.3, Mac OS 10.4 (or later). Mac mini.
So that's why I'm confused. I've sent them an e-mail asking for iMac compatibility but they haven't answered yet. That's why I came up here in search of some advice or maybe someone who already tried the product on its very own iMac.