A lumber tag takes the form of a rectangular plate (1) having information on the working face (2) thereof and four mounting teeth (4) at the corners. Four wedge-shaped grooves (14) are situated adjacent the teeth, on the short sides of the plate. Fastening means are provided on the rear face (3) of the plate, said fastening means being in the form of two symmetrical wave-shaped protuberances situated along the edges of the short sides of the plate, perpendicular to the rear face thereof. The rear face of the plate is further provided with two protective elements (6) in the form of two symmetrical wave-shaped protuberances situated perpendicular to the rear face of the plate, along the edges of the long sides thereof, symmetrically about an axial line that passes through the centre of the plate and is parallel to the long sides thereof. The height of the protective elements is less than the height of the fastening means, and their peripheral portions (12) extend into a region (13) occupied by the fastening elements and overlap with the projections of said fastening elements in a plane that passes through the longer axial line of the plate and is perpendicular to the rear face thereof.
