The Grove - 4-Channel SPDT Relay has four single pole - double throw (SPDT) switches. It only requires low-voltage and low current signals to control the switches, specifically, you can use 5V DC to control max 250V AC or 110V DC.
They have used an on-board STM32F030F4P6 to control the channels separately. The control commands are transmitted via the I2C interface, the on-board STM32F030F4P6 will parse the command, so that you can control the switch you want.
Some applications of this relay are: