Paving specially adapted for through-the-surfacing drainage

Official title: {Paving specially adapted for through-the-surfacing drainage, e.g. perforated, porous; Preformed paving elements comprising, or adapted to form, passageways for carrying off drainage (E01C9/004, E01C9/008, E01C9/08, E01C9/10, E01C11/228, E01C13/00 take precedence)}

E01C11/225 (Paving specially adapted for through-the-surfacing drainage) appears on 199 US grants and 220 published applications in this corpus.