The Siemens 3TK2805-0BB4 is a SIRIUS safety relay expansion module, engineered to increase the number of safe outputs in a machine safety system. Operating with a 24V DC rated control supply voltage, this module is designed to be used with a basic safety relay to expand its functionality. It is ideal for complex safety applications that require additional enabling circuits, such as monitoring multiple emergency stop pushbuttons, safety gates, or light curtains. The module features user-friendly screw terminals for a secure and reliable connection, ensuring robust performance and easy integration into existing safety circuits. By providing additional contacts, the 3TK2805-0BB4 helps systems achieve high safety levels up to SIL 3 and PL e, ensuring comprehensive protection for both personnel and equipment.