The latest Arduino Relay Module use high-quality Relay by NingBo HuiKe.

It provides all input and output functions, Integrated dynamic indicator of the module .It also can show the relay’s open and close status, protecting AD hoc free-wheeling diode , the highest can be connected with AC250V/3A or DC30V/3A equipment, thus can be controlled through Arduino controller, converting weak current controll into strong current control.
Many large current or high voltage devices (such as electric fan, etc.) are usually not directly with Arduino or other SCM digital I/O interface to control when using Arduino to design interacting works, then you can use this digital relay modules with a 3p sensor connecting line directly inserting into Arduino Sensor shield V5.0 or Arduino MEGA sensor Shield.