High energy, high surge capability. Two and three terminal surge arrester. Enclosure is painted steel, mounting centers 10 ¾” X 6”. Housing 10” X 8” X 4”. Two terminal type for bipolar protection between two points, e.g. plus to minus, or plus to ground, or minus to ground. Three terminal type for bipolar protection between three points, e.g. plus to minus, plus to ground, minus to ground.