Relay Module is suitable for switching small power appliances - e.g. LED strip, cooling fan, siren, buzzer, garage door opener, etc.
A cool feature of this module is a latching relay (also called bistable relay). This feature makes this module suitable for battery-operated applications. What does it mean? For this type of relay the energy is needed only during transition state of the relay. Once the new state has been set it is not necessary to energize the coil anymore - it will simply "remember" (or latch) its state. Switching period is indicated using green LED (software defined "true state"), or using red LED (software defined "false state").
This module is I2C-only peripheral so it does not allocate any extra signals from BigClown header.