Edge-lit exit signs spread light uniformly across their face to optimize visibility for marking exits and passages toward exits to guide people out of buildings. Their slim housing has a more upscale look than typical box-style exit signs, making edge-lit signs a preferred choice for hotels, conference rooms, and offices with high-end furnishings and finishes. They mount near exit route doors and doorways and hardwire into an electrical system that keeps them lit for visibility. Signs with battery backup switch to their battery during a power outage. Signs without battery backup are commonly used in buildings with emergency systems that supply power during an outage. The included arrows or chevrons attach to the signs to indicate the direction of travel to the nearest exit if the path is not immediately apparent. Local safety codes may require that lighted emergency exit signs be made of a specific material and have lettering and graphics of a specific color, size, and arrangement.