The Relay Shield v1.1 is an Arduino compatible smart module with 4 mechanical relays providing an easy way to control high voltage. The max switching power is 35VDC 70W for each channel. It can be directly controlled by Arduino/Crowduino through digital IOs with external 9V DC supply. Compared to the Relay shield 1.0, the v1.1 version use 4 selector instead of those push buttons used on version1.0, to make it more convenient to control the relays manually.
Note: Please note that the pins on relay shield should not touch the USB connector of Arduino UNO when they are connected.