The close these doors at night 5124 sign ensures that doors are kept closed throughout the night. The white words appear on a blue circular background and are effective in communicating this rule. Display the signs as close to eye level as possible for people to see.
As the sign is AAA photoluminescent, it would even glow in the dark if there were a lack of light. People may not be aware of this rule unless you use the sign to advise them.
Fixing requires anything as simple as sticky pads, 'No-nails' type adhesive or double-sided tape.