The Grove - 2-Channel SPDT Relay has two single pole - double throw (SPDT) switches. It only requires low-voltage and low current signals to
control those switches. Specifically, you can use 5V DC to control max.250V AC or 110V DC.
The best thing is that you can control the two channels separately. For instance, controlled by SIG1, you can connect the COM1 to NC1 or N01 as your wish.
It is so convenient and reliable that it can be applied to massive products or projects which need to switch high voltage/high current devices.