AR9B291 is a normally closed (NC) contact block designed for use with Fuji Electric's AR22/DR22 and AR30/DR30 series command switches. This contact block features a 1NC (one normally closed) configuration and is color-coded red for easy identification during installation and maintenance. The block measures 19.3 x 29 x 27 mm and is compatible with both standard and overlap mounting options (AR9B291 and AR9B291-S variants). It integrates seamlessly with the modular command switch system, allowing tool-free replacement and addition of contact configurations. The AR9B291 is commonly used in industrial control panels, machine tools, and instrumentation systems where reliable NC switching is required for safety interlocks and control logic.