National Marker Safety Signs alert employees and visitors to the hazards, general rules, and exit locations in or around your workplace. Various sizes, materials are available. Safety signs are available with or without a Danger, Caution, Warning, Notice and Think Headers. Don't see the exact wording, size, or material you need? Custom Signs are available in as little as 24 hours! Fire signs comply with NFPA standards for fire safety identification. Signs are also available in a variety of materials. Safety Labels are printed on pressure-sensitive vinyl for application on almost any surface.