Features:
Input Power: 5V DC (160MA)
5V solid state relay 240V 2A, the output with a resistive fuse 240V 2A.

Size:
2 Way: 55 * 33 * 25 (L * W * H)
4 Way: 57 * 55 * 25 (L * W * H)
8 Way: 106 * 56 * 25 (L * W * H)

The Input Control Signal Voltage:
High Level Module: (0-2.5V state low level relay ON)
(3.3-5V state high level relay OFF)
Low Level Module: (0-2.5V state low level relay OFF)
(3.3-5V state high level relay ON)
There are 2.54CM pin and blue KF301 terminal control line is more convenient.

Input Section:
DC +: Connect the power supply positive (according to the relay voltage)
DC-: Connect the power supply negative
CH2: 2-channel relay module signal to trigger the end (high level trigger effective)
CH4: 4-channel relay module signal to trigger the end (high level trigger effective)
CH8: 8-channel relay module signal to trigger the end (high level trigger effective)

High and Low Meaning:
High-level trigger refers to the signal trigger side (IN) and the negative power supply has a positive voltage between the positive and the power supply is usually connected to the trigger side of a trigger, when the trigger side voltage or trigger to reach the trigger Voltage, the relay is pull.

Low-level trigger refers to the voltage between the signal trigger terminal and the negative terminal of the power supply is OV, or the voltage of the trigger terminal is lower than the voltage of the positive terminal of the power supply. When the voltage is low enough to trigger, the relay is pulled in, The negative side of the power supply is connected to the trigger side of a trigger, so that the relay is pull.