original early 1950's american industrial "new old stock" single-sided stamped or pressed steel "think!" factory machine shop sign likely designed and fabricated by the ready-made sign co., new york city, ny. the bright cherry red enameled sign would be used in work environments where careless use of machinery and or activities could result in injury or death. the bold white lettering and rounded edge border is slightly embossed or raised from the otherwise flat surface. the single-sided steel sign remains in great overall condition. only one available. 10 inches x 2 1/2 inches.