The Nipper is a tiny 17x17x17mm cube and it weighs just 10g. Nipper simply opens and place two AA batteries inbetween the magnet and connect it to the phone. It is compatible with Samsungs, LGs, Blackberrys, HTCs, Nokias and Kindles. A charger for Apple phones is in development.
For a modern smartphone, the Nipper will give an extra 10% battery capacity in 30 minutes, and 20% in just over an hour. The Nipper contains three neodymium magnets. They have the double function of holding the batteries together while at the same time making an electrical connection to the Nippers circuit board. This circuit is called a boost converter, it turns the power from the batteries into a 5V power supply to charge your phone.