HF49FD0121H21G Relay 12VDC is a compact general purpose relay designed to switch electrical loads using a 12 V DC control signal. This listing includes 10 pieces. Key benefits Enables lowcurrent control signals to switch higher power circuits, providing safe isolation between control electronics and loads. Compact form factor suited for spaceconstrained projects and PCBbased designs. Reliable, proven relay technology suitable for a wide range of hobbyist and professional applications. Simple integration with standard 12V DC control systems and logic. Key attributes Model: HF49FD0121H21G Series: HF49FD Coil voltage: 12 V DC Type: Relay Quantity: 10 pieces per Brand alignment: HF49FD family (consistent with existing HF49FD specifications and features) Functionality and performance Electromechanical switching for isolating and routing signals in control circuits. Designed for general purpose switching in electronics and automation applications. Provides a robust interface between low voltage control logic and higher load circuits, suitable for a variety of switching tasks. Compatibility and suitability Compatible with standard 12V DC drive signals used in hobby electronics, automation, instrumentation, and control panels. Appropriate for projects requiring a compact relay with a 12V DC coil to control loads in a safe, isolated manner. Use cases Microcontrollerbased projects: trigger a 12V load such as a small motor or solenoid from a lowcurrent controller by energizing the relay coil with a 12V signal. Home automation: switch auxiliary circuits (lights, sensors, or other 12V devices) via a dedicated control output while maintaining isolation from the load side. Small automation panels or instrumentation: provide reliable signal routing and switching between control logic and powered devices in compact enclosures. Notes This description reflects the model HF49FD0121H21G and packaging of 10 pieces per . For exact contact form, contact rating, and mounting details, refer to the HF49FD datasheet or manufacturer specifications.