You wont need to rub this lamp to get it to work!
Once its charged you can slide the lid open to vary the amount of light given out. This is effectively an on/off switch on a light that can be charged an infinite number of times.
You can charge it in sunlight or with a blast of a flashlight effectively making the batteries last longer.
Its powerful enough to read a map by or find your way around a room, signal, light a tent and a host of other uses. Its reliable, simple and will last for many years.