Plain Desiccators are physically the same as Vaccum desiccators. Only difference is the absence of stop cock. Grease should be applied on the flanges to make it air tight. Both Vaccum & Plan Desiccators are provided with a thick perforated Polypropylene disc with a big hole in the centre for easy lifting. The tiny holes in the disc provide air troughs & support to the dishes. However porcelain discs are advisable in case of incandescent crucibles.