Abstract: A method of constructing a desiccant pot by trapping a spun-bonded low density membrane between two separate parts constituting either the pot lid or the pot body, these two separate parts being made of high density plastic, and then fusing the membrane and the separate parts together, in which one of the separate parts has upon its touching surface an energy directing protrusion, arranged such that when the three components are assembled so that the two separate body and lid parts are pressed together with the membrane between, the energy directing protrusion extends from one touching surface to the other to space them slightly apart.