System and methods are provided. The openingclosing mechanism and the disengaging device are held in a common casing. A second step is carried out to coat a collector with said coating solution to form the polarizable electrode layer on the collector. The event’s disposition determines whether the event is allowed or disallowed and what action, if any, should be taken by a system monitor in response to that event. This system comprises a registered commodity data storing unit storing a desired sale or purchase price of a commodity, and the information about a change condition and a change price of the desired sale or purchase price, and a unit changing the price if the information about the change condition or the change price, which is stored in the registered commodity data storing unit, is satisfied. Disposing the fixing ring below the flexible membrane in the lower recess after insertion of the outer flange of the flexible membrane into the retention groove results in fixing of the outer flange of the flexible membrane within the retention groove.