This surge protection device from Square D is a type 1 device that can be used with or without an over current protection device. This device can be used indoors or outdoors to provide surge suppression for 1 PH, 3 wire, 120/240 VAC or 2 wire, 120 VAC systems. With a short circuit current rating 25 kA, back nipple mounting, and NEMA 4X rating, this compact design can be placed adjacent to power panels. The unit is set for NEC, CSA, and UL standards.