The MGT-1850 Class II AC Power Supply from MG Electronics is designed to provide 18VAC, 50VA power to equipment that require you to run your own power cable to custom lengths. It features a three-prong grounded North American plug with a retaining screw, intended to replace an outlet plate screw, to hold the power supply securely in-place and prevents it from being accidentally unplugged. Its recessed three-screw terminal block has the positive and negative terminals on the outside with a ground terminal in the center. A green LED on the forward-facing side of the power supply lets you know that it is getting power.