This DFRoobot relay shield V2.1 is a completely new desgin which is capable of controlling 4 relays. The max switching power could be DC 90W or AC 360VA. It could be directly controlled by Arduino/DFRduino through digital IOs with external 9v supply. With buildin xbee type socket, it can be wirelessly controlled via Xbee/bluetooth/WPM. Make it an ideal solution for home automation and robotics purpose.