A switch assembly for a wetdry vacuum cleaner is disclosed. The o-ring is slidably received between the at least one projection of the cage and the central portion of the cage so that the cage is axially fixed with respect to the shaft. The non-aqueous light-curable ink composition stored in the ink container has a dissolved air content of 7 ppm or more. Further, the resulting configuration allows to ABS modulator to be located in a portion having a high rigidity without occupying a space for other components, such as an induction system. Also included is a method for reducing an effect of a tube wave. A push-button actuator exposed to the exterior of a fluid container to which the dispensing valve is attached is provided for actuating the dispensing valve, the actuator comprising a circular push button concentrically mounted on a breakaway rim.