Other hand cranks are available, but this is the first time one has formed part of a phone case.
https://www.youtube.com/watch?v=p6hifnl_B08
Charging your phone using a built-in hand crank
A smartphone case which is capable of charging your phone using a built-in hand crank has gone on sale. Five minutes of cranking can provide about 20 minutes of talk time or an hour’s worth of smartphone usage.