The Siemens 3RH1921-1DA11 is a front-mounted auxiliary switch block designed for seamless integration with SIRIUS 3RT2 contactors and 3RH2 contactor relays. This reliable component extends the functionality of your control circuits by providing additional signaling contacts. It features one normally open (NO) and one normally closed (NC) contact, making it versatile for various monitoring and interlocking applications. The unit is designed for quick and secure snap-on mounting and utilizes dependable screw-type terminals for easy wiring, ensuring a stable and long-lasting connection in industrial environments.