Like most rugged smartphone cases, these all use a strong plastic shell that protects your phone against drops on hard concrete. (tomsguide.com)
This case has been tested to provide complete protection from drops from up to 6.6 feet (two meters) onto hard concrete surfaces. (heavy.com)
Neither have I firsthand knowledge what the effects are of jumping off a bridge, but I can see how high it is and how hard the concrete underneath it. (goodereader.com)