In a slide detector, a contact member provided on a slider is made of gold or a gold alloy including an abrasion resistant metallic component, and a plurality of electrodes provided on an electric insulating board is made of a silver alloy including glass. This carton also has a panel dispenser flap that is easily removed from a top or bottom panel of the carton to expose a dispenser which has a bottom of sufficient height from the end of the carton on which it is resting while dispensing containers to prevent the containers in the bottom row from falling out, but less than the diameter of a container in the carton. The trigger has a trigger lever being pivotably disposed therein. The EM detector detects an EM signal that is synchronized with the acoustical signal. When the engaging portion of fixing member engages with the slice of supporting tray, the motherboard is in a locked state; when the engaging portion of fixing member disengages from the slice of supporting tray, the motherboard is in an unlocked state.