The Siemens 3SB3500-4DL11-ZB01 is a 22mm round metal key switch designed for secure and reliable control applications. This model features a three-position switching mechanism labeled I-O-II, with a positive locking angle of 2x50 degrees, ensuring precise operation and clear position feedback. The switch comes with two keys and allows key removal in all three positions for enhanced safety and operational control. It also includes a mounting bracket for straightforward installation. Additionally, the product supports special keying options such as SB30, SB31, and 421 to accommodate specific security requirements. Distributed by BSP Automation, this key switch is well-suited for industrial environments where secure and durable operator interfaces are essential.