With the original Smartphone-to-Smartphone charging jumper cables you can plug two Android phones together to get a little juice to wake up your dead android smartphone. Yes, you are reading that right. Unfortunately it’s not available for Apple. The cables have been tested on an extensive range of Android phones, but the inventor makes no assurances it works on all Android phones.
Just plug both ends into the microUSB ports of the two Android phones and observe how your battery indicator reach it’s battery increasing again! “As long as you're with a friend that has a fuller battery than you, you won't need the municipal power grid or a portable battery around - just a 16g cable!”
Pleased be advised that there are particular requirements for the charger smartphone to be capable to make use of this jumper cable. Again, it is not working for iOS devices.
Here are some added info about the Smartphone-to-smartphone jumper cable.