The Groen Z016028 Kettle Red Signal Light 1/2" 250V lights when electrical current is flowing through its 1/2" red lens, which provides a visual response of system operation. It is fitted to 250V circuits and works by responding to certain electrical signals to enable operators to check the status of equipment. This is mounted on the control panels, close to switches or machinery, so ... https://partsfe.com/z016028-groen-signal-light-12-red-250v