EK-3399ES is a universal air conditioner remote control thatconverts light energy into electric power. It has a built-instorage capacitor and does not need to use traditional drybatteries. Users only need to put the remote control next tothe window or balcony at home to absorb the light. Absorb-ing the sunlight for 3 to 4 hours can generate sufficient energyto allow the use of remote control for 3 months or more.(Note: It is not recommended to expose the remote controlunder strong sunlight for a long time.) By converting light toelectricity, you can enjoy the wonderful life of green energy！