the photoluminescent exit> legend of these elegant acrylic signs absorbs and stores energy from ambient fluorescent light. Signs are easily visible in the event of a sudden blackout. Signs are ul924-listed by etl – intertek testing. Non-electrical, non-radioactive signs are maintenance free; no mechanical or electrical power source required and will last 25+ years. Meet nfpa 101 – life safety code, jcaho and osha requirements. Meet current building codes including ibc, ifc, icbo, boca, sbcci and nfpa. Leed qualifier. 50-foot viewing distance. Suited for high-location and floor-proximity installation. Each sign has four holes for flat wall mount. Optional: add one set of four stand-off barrels (item-no.: 600058) for elevated wall mount which gives the acrylic sign an even superior look where appealing design is of importance.