A steaming oven having a collector plate disposed in an oven chamber. The base material includes a primary component and a secondary component, the primary component including Al2O3 and the secondary component including tetragonal-ZrO2. A noise suppressor component is within the outer body of the firearm suppressor. Cam portions are provided on respective surfaces opposite to each other of an intermediate flange and an outer flange so as to mesh with each other. The zoom lens should satisfy at least one of conditions to.