Twist-To-Release Operator, 2-Position, M22, Red Mushroom, 40mm22. 5 mm, Non Metallic Heavy Duty Twist to Release Emergency Stop Operator, 40 mm Diameter, Non Illuminated, Red Plastic, Maintained Latching. NEMA Rating: 4X, 13. ***Includes: Contact Block Holder*** The M22 line includes 35 mm, 45 mm and 60 mm Emergency Stop buttons with internationally accepted twist to release functionality. All are available in both keyed and non keyed versions; illuminated and non illuminated. A unique lighting ring is available