These solid state relay (SSR) allows you to control high-curent AC loads from lower voltage DC control circuitry. You can interface it directly with Arduino and Raspberry or even you can use the 3V coin cell with switch to control the AC line. Solid state relays have several advantages over mechanical relays. One such advantage is that they can be switched by a much lower voltage and at a much lower current than most mechanical relays. Also, because there’s no moving contacts, solid state relays can be switched much faster and for much longer periods without wearing out. This relay comes with indicator led to notify when the load is ON.
This particular SSR can switch current loads of up to 20A with a 3-32V DC input and a zero cross trigger control method. These are equipped with four screw terminals (for use with ring or fork connectors) and comes with plastic cover that slides over the top of the relay to protect the terminals.
Image and content taken from Sparkfun