[Ann in Arlington]

It's not magnetic. I would guess it's aluminum but with high-tech plastics today I can't rule that out. I would think some one from Amazon would frequent these boards and have a positive answer. Thanks so far for your help.

I'm 100% certain that someone from Amazon monitors KindleBoards.

I'm nearly as certain that they aren't allowed to comment. . . .

I'm also pretty certain that someone who has researched or figured it out will share.

If I may ask the OP: Why are you asking? I can't think of any reason why it would be important to know. And, to my recollection, it's the first time it has been asked here. Though there was much discussion about the difference between the backs on the 2nd vs 3rd generation Kindles.