This pack includes 20 pieces of G3MB-202P-5VDC relay modules. They are compact, 4-pin PCB relays designed for easy integration into control circuits. Key benefits - Reliable isolation between control and load circuits for safety and reliability - 5V DC coil drive (variants exist for 12V and 24V) with a 2A at 240VAC contact rating, suitable for lights, small motors, and other moderate loads - Simple 4-pin footprint for straightforward PCB mounting and replacement - Fast, repeatable switching with predictable performance in compact control panels Specifications at a glance - Coil voltage: 5V DC (G3MB-202P-5VDC) [other coil voltages available in other listings] - Load: 2A at 240VAC - Configuration: 4-pin Typical applications - Home automation: control lighting or fans from a microcontroller or PLC - Small automation panels: switch AC devices like pumps or heaters in compact enclosures - Prototyping and education: teach and test relay-driven control circuits with safe isolation Safety and usage tips - Drive the coil with a suitable transistor/driver and include a flyback diode for DC loads - Ensure the load current stays within the 2A rating and observe proper wiring