Siemens 3SB3921-0AK

The Siemens catalog number 3SB3921-0AK refers to a protective collar designed for use with round pushbutton and selector switch units in plastic or metal housings. This collar, which mounts on the front panel, measures 22 mm in diameter and features a yellow finish for clear visibility. While this model has been succeeded by the newer 3SU1900-0DY30-0AA0, it remains a reliable option for applications requiring robust front panel protection. BSP Automation offers this product as part of their extensive range of industrial control components.