Keychain and helium-proven iPhone do not mix in the same pocket - the back has silver colored speckles after some time. This disadvantage was me known in advance and bothered me less. Here's function before beauty - an unattractive appearance is also a 'security feature'.
Overall, I was extremely happy for a good five months with the Juice Pack Helium.
I use the iPhone sometimes without spare battery. Unfortunately, the inner holder was last when you open the Juice packs in 'bottom fifth' solved with the Lightning connector of the outer shell.
I have no evidence found that this case is far occurred more often. During my research on the problem but it turned out that Juice Packs for product pirates are desirable. In retrospect, I'm glad to have acquired the Juice Pack for some extra money directly from Amazon, because the handling of complaints and redemption through Amazon was exemplary.
As a substitute I have now (again directly from Amazon) acquired the Juice Pack Air, because the whole construction of the battery pack makes a stable impression.