Can anyone Identify what this unit is and what it does.?

Question

The unit is a Siemens 3RK1904-2AB01 It was in a bag I was given and nobody knows what it is or what it does. I need to find out what it does and who wouyld use it. Any help would be great. Thanks

Answer 1

It's an interface addressing module for programmable logic controllers. New ones cost 289 Euros. Used in industrial automation.