This is an information board installed in the expressway service area to provide parking lot availability and other information to drivers using the facility. As with facilities on expressways, anti-loosening measures are required for installation.

• Places susceptible to wind pressure and vibration.
• Seaside areas that are prone to corrosion.

• Unlike when using a general double nut, it is no longer necessary to tighten the wings.
• The thread is no longer damaged when the bolt is screwed in.
• The maintenance period has been greatly extended.