National Marker Company sign with legend âCAUTION â EYE PROTECTION REQUIRED WHEN OPERATING THIS EQUIPMENTâ is commonly seen at industrial facilities and construction sites to enforce personnel safety standards. The caution sign clearly informs worker that they must not operate without wearing the eye protection. It displays the message in bold yellow text on a black base and in black text on a yellow base, ensuring better visibility. The caution signage has NMC Sign Muscle coating to protect the text against fading, scratches, scuffing, mold, and moisture and complies with OSHA standards.