National Marker Company sign with legend âCAUTION â WATCH YOUR STEP â USE HANDRAILâ informs the visitors and employees that they should use the handrail and proceed carefully. It is often seen in and around the staircase area in both commercial and residential buildings. The caution sign has clear, bold yellow text on black base with black text on a yellow base to ensure clear visibility and readability. The material is UV resistant, chemical resistant, graffiti proof and has NMC Sign Muscle coating that protects the text against fading, scratches, scuffing, mold, and moisture.