The AR30PR-311B is a 3-position maintained selector switch with a round knob operator and 1NO+1NC contact arrangement, designed for industrial control applications. The switch features a maintained operation with each position rotated 45° and is equipped with a black knob (standard color code B), with other colors available upon request. The contact block provides one normally open and one normally closed contact per position, allowing flexible circuit control across three discrete positions. The switch conforms to IEC Standard IP65 protection level with oil-and dust-proof operator module construction, ensuring reliable performance in dusty and moist industrial environments. The compact design and quick-replacement contact block construction make it suitable for machinery control panels, process automation, and equipment selector applications where reliable multi-position switching is required.