HMCP400Y5C, Cutler Hammer / Eaton / Westinghouse, Series C, type HMCP, K Frame, 3P, 3PH, 400A, 600V, 35kA@480V, feed-thru, complete with I - Instantaneous Protection Only and non-aluminum line & load side lug terminals, magnetic range 2250-4500A, magnetic only, molded case circuit breakers