I remember Japan as a land of gadgets: there is no end to what this country can invent.
I remember a friend of mine who gave me a book filled with Japanese gadgets, including this small table you can “wear” in front of your tummy (the table is hanged much like the cigarette tray worn by cigarette girls in the US in the 40s) so that you can lay your forearms there while you walk, just in case you are too tired to swing your arms.
The cell phone battery chargers, such as the ones shown in the picture, are almost everywhere in Tokyo: in cell phone stores & service centers and in photo processing places, to name a few locations. I have only seen these machines in Tokyo but have not spotted them in Europe or South East Asia, and for sure, not in the US.
As the name implies, this device charges your cell phone battery. When you are away from home and find out that your cell phone is running out of juice, you go where you can find these devices, figure out which drawer to open (each drawer is specific to a certain model of cell phone).
First, you punch in that drawer number, and if the drawer is available (empty), it pops open. Then you put your phone in there, connect the supplied cord to your phone, closed the drawer, punch in your code (usually it is your cell phone security code) and the drawer locks itself automatically. You can leave the phone there securely (unless someone actually steals the entire machine filled with these phones).
Upon returning, you punch in the same security code, and voila, the drawer opens, and you retrieve your phone with its battery fully recharged. In other places and providers, some fee may be charged for the use of this machine, but at least with Vodafone Tokyo, the service is free.