IEC 60947-1, EN 60947-1 IEC 60947-5-1, EN 60947-5-1. 22 mm Selector Switch Heads, Plastic. Siemens extremely rugged IP69K high-grade plastic selector switch heads. Self-holding function of the actuator when mounting Twist prevention integrated into patented holder design Suitable for use in extreme environments No special tools required Simple geometry for mounting holes