Related Clues:

• Light stuff
• Light stuff?
• It may glow in the dark
• Diner sign filler
• Sign stuff
• Vegas light source
• Light material
• It lights up Las Vegas
• Substance in some signs
• Motel sign filler
• Nightlife sign's light source
• Store sign filler
• Stuff in some signs
• It glows orange-red when placed in an electric field