Lighted exit signs hardwire into an electrical system that keeps them lit for visibility. They mount near exit route doors and doorways, marking exits and passages toward exits to guide people out of buildings. 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. 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. General purpose signs install in dry, nonhazardous locations such as schools, offices, and commercial buildings. Edge-lit signs provide uniform light distribution for better visibility and a slim design for a more upscale look than typical, box-style exit signs. Wet location signs withstand exposure to water. Vandal-resistant signs resist impacts and tampering in high-abuse or rough service areas.