Shock Resistance: NewerTech NuGuard KX Case for Apple iPhone 4/5
Well, I finally put a case on my iPhone 4s, because it eliminates several issues for me: grip, handling, reduced tendency to go on vibrate mode, drop protection.
Read about my usage of the NewerTech NuGuard KX case for iPhone 4 or iPhone 5.

NewerTech NuGuard KX Case for Apple iPhone 4/4s/5/5s
Click for larger image of all color choices.

NewerTech NuGuard KX Case for Apple iPhone 4/4s/5/5s