Relay Module 4-Ch 5V with Optocouplers.

4-Channel relay module.
Inputs Gnd, Vcc (5Vdc), channel select signal 1-4 (active low).
Channel signals are optically isolated from the relay coils.
Option to isolate the signal-side Vcc from the relay-side Vcc using a removable jumper.
3-way terminal blocks connect to SPDT changeover relay contacts.
Relay contacts rated at 10A 250Vac, 15A 125Vac.
Relay coils 400mW each.