Siemens 3SB3500-4RR51 Actuator Switch Lock And Key

Siemens 3SB3500-4RR51 is a 22 mm metal round actuator key-operated selector switch with two keys included, designed for control panels and machine guarding where a keyed selection is required. It provides a three-position I–O–II configuration with left-latching operation and is compatible with standard 22 mm panel cutouts. The actuator is a metal round head, offering robust durability in industrial environments. As part of the Siemens 3SB3/3SB35 family, this device is intended to provide secure, two-key access to select machine functions or settings, helping prevent unintended changes. Its compact 22 mm footprint and metal construction make it suitable for panel installations in manufacturing, packaging, and other heavy-duty applications.