This is a vintage industrial-style warning sign featuring the embossed lettering "DOOR MUST BE KEPT LOCKED AT ALL TIMES." Constructed from durable galvanized steel with a matte black finish and raised white text, the sign has a substantial, tactile quality typical of mid-century security or institutional signage. The reverse side reveals the classic spangled pattern of the galvanized metal and includes four original adhesive mounting brackets. It is in good vintage condition, showing authentic character with minor paint wear along the edges and some surface oxidation on the rear mounting tabs, consistent with its age and previous use.

Dimensions: 28.5cm x 13.5cm