A prosthetic foot can include a plate-like foot member extending along a longitudinal axis between an anterior end generally corresponding to a toe portion of a foot to a posterior end, and a metatarsal hinge comprising an elongate groove extending between medial and lateral edges of the foot member. The plug-in connection connects hearing tubes, sound tubes or electrical signal lines. A retardation layer is formed over the first conductive layer and a dielectric layer is formed over the entire surface of the multi-layer structure, the entire surface of the conductive region and over the surface of the substrate. As part of the request, the passcode is provided. The same apparatus, but with the use of cold air to cool the product, rather than hot air to heat and dry a product, is also within the teachings of the present invention.