The TSRB430 provides four volt free contact relay outputs with a current rating of up to 30Amp each. The module is powered from a 12vdc supply. The DC input jack is 2.1mm with positive core polarity, DC supplies are required to supply at least 1A at 12vdc. The relays are SPST-NO types.
It's a Bluetooth relay, You can easily control this relay module by your computer or smartphone using bluetooth. The communication way also can be changed easily. Remove the Bluetooth Bee module instead with a WiFiBee, it becomes a WIFI relay. It will be a USB relay when you plugged a USBBee. Very convenient to use.