A power supply system includes a main power storage device and a plurality of sub power storage devices. The online system may include both sellers of products and lenders that offer financing to buyers seeking to purchase the products. Each of the tension members includes a shaft having an upper end locked by the face plate and a lower end penetrating the base plate and a coil spring that is positioned on the base plate and biases the lower end of the shaft downward. The present invention also includes an optical transfer system having a light source and an elliptically configured waveguide device.