This 6ED1057-4EA00-0AA0 part is a Siemens LOGO! 12/24RCE logic module. Specifically, it is an expansion and communication module that includes a self-contained USB port or a master/slave port, making it suitable for either 24 V DC or 12 V AC control. It has 24 inputs and 8 normally open relay outputs. The outputs can be used to control a variety of devices, including pumps, motors, valves, actuators, and lights. The inputs can be used to detect the presence or absence of external stimuli, such as sensors and switches. It also has 8 status indicators and 8 counter/timer/clock functions. This module can be used in a variety of industrial and commercial applications.