Since there is a lack of back shells with a metal or magnetic strip, I decided to buy the 3M EMI absorber sheet I've seen mentioned in a few threads. I tried it first in the Apple Smart Case, but the hold was very weak. I'm sure it would hold perfectly with the tape on the outside of the case, but I don't want to ruin my leather case. I then tried it in a TPU case with Apple Smart Cover. The hold still isn't as strong as I'd like, but it's definitely better than with the Apple Case. See pictures attached. I bought the sheet here: http://www.mouser.com/search/ProductDetail.aspx?qs=RnLyf%2bIy6kHmYlTFx3Fyrw==. I cut a strip and stuck it to the inside of the case.