When there are structural limitations that do not allow direct operation on the wall, the pocket door, which slides and camouflages itself inside the wall, will be replaced by the external wall door, which slides outside the wall. The difference, therefore, between the two models is the absence of the cavity: it is in fact possible to insert the door panel inside a track that will make it visibly slide outside the wall. Thus, the external sliding door replaces the wall itself as a highly decorative design system.