sleeve with LED / writing help

This rubber sleeve could converge energy by pressing it. And the rubber sleeve will change the kinetic energy into electric energy which lights the LED in the front of rubber sleeve. When you write something in a dark environment, please switch on the LED light. It can illuminate your notebook and it wouldn’t bother others. It will be more convenient to write in the darkness and it is energy-saving. When the electric energy is used up, the rubber sleeve can be recharged by pressing it.