A display stand has a base, a vertical pole having a lower end fixed to the base. On a first face of the semiconductor substrate is formed plural units which is constructed of image sensors and plural contact terminals. The value of the first axis of the calculated coordinate values is compared with a predetermined value. A remotely-activatable valve allows user’s to selectively shut off the flow of fluid. The standard bulb sockets are configured and dimensioned to releasably operatively receive only standard bulbs, and the fuse bulb socket is configured and dimensioned to non-releasably operatively receive a fuse bulb. The equalization may be based on suppressing the low frequency components of the phase error signal.