Canon EP-EX15 II? What's the difference?

So while surfing around B&H's website I came across new (well, new to me) eyepiece extender. Anyone know about about this and what they changed? Here is the search LINK showing both eyepieces at B&H, and here is a pic of them both:

EP-EX15:

I don't know what the difference really is, but one thing I do know is that the "II" version fits my 40D.

From the look of the photos it looks like the new one will allow you to put an angle finder or other accessory on the camera without removing the eye piece. This will be good so if you have a diopter installed you will not be removing it.

Of course I could be wrong and be thinking of the diopter eyepiece adapter.

do you know if the mkI fits on the 40D?

keitaro wrote in post #6549578
do you know if the mkI fits on the 40D?

Yes it does, I have used mine on both my 40D and 5D.

Huh, I might buy one just to find out! lol