SMAKN&reg; low level trigger 4-channel 5v Solid State Relay Module Board SSR Has been assembled, and electrical test passed. Led indicator for each relay. Size: 78 x 55 x 24 mm (approximately 3.1 x 2.17 x 0.95 inch) Input control signal voltage: 0V - 0.5V Low stage (SSR is OFF), 0.5V - 2.5V (unknown state), 2.5V - 20V High state (SSR is ON); SSR Output (each channel); Load voltage range: 75 to 264VAC (50/60Hz); Load current: 0.1 to 2 AMP Standard interface that can be controlled directly by microcontroller (Arduino , 8051, AVR, PIC, DSP, ARM, ARM, MSP430, TTL logic)