90840 Brady Worldwide Double Sided Exit Sign with Mount, 3TY23Product Description Model : 90840 Unit : Each Description : Double Sided Sign with Bracket Color : Red Photoluminescent exit signs are steel encased glow in the dark plastic panels. These signs provide consistent and highly visible illumination immediately after the lights go out. Signs absorb and store energy from ambient light. They use zero electricity and do not require special wiring, maintenance, a backup power source, or professional