Eaton XTCS400M – Auxiliary Contact Block with Integrated Surge Suppressor The Eaton XTCS400M is a side-mounting auxiliary contact block from the specialized XTCS series, designed for use with large-frame Eaton contactors, primarily the DILM400 and similar models. The key distinguishing feature of this module is the integrated surge suppressor, denoted by the “S” in its model suffix.