Pilot lights and indicator lights illuminate to signal that a machine’s process has started, stopped, or is experiencing issues. Also known as power indicator lights, they install on machines and in control panels to help keep workers safe and equipment operating smoothly. Modular pilot light assemblies are interchangeable with lamp modules and lenses. Single-piece monolithic pilot lights are complete assemblies without seams that provide more environmental protection than modular pilot lights. However, they come as is and cannot be altered. Hazardous-location pilot lights are for environments where flammable gases, liquids, particles, and other combustible materials are present. Heads for pilot lights are the front of the assembly that holds the lens. Lenses for pilot lights are transparent covers that fit over the pilot light head to enhance visibility and help protect the light.