A roll for smoothing a web, a process for making the roll and a process of repairing the roll. An electronic unit for optical detection of the plantar surface of the human foot assigned to the support stage, in each instance, is arranged underneath each tread. The screen frame and screen mesh are in tension when the screen resides in the door or window opening. The hoods can be extensions of the hearing aid receiver at the front end of the receiver. According to the invention, on its face immediately adjacent to the pressurized space, the door is provided with a projecting lip in the vicinity of its free edge, accelerating the opening of said door in the event of decompression of the space. One advantage of the present invention over a soft gelatin capsule containing the same formulation but comprising gelatin extracted by an extraction process comprising alkali pre-treatment of the collagen source is that the present invention does not harden significantly over time and thus has a longer shelf life.