This light has a self contained changeable battery and tiny on/off slide switch
Measures 1-7/8" high x 1-1/4" deep x 3/4" wide
LED Lamp. No transformer required. Turn on and off with small switch on Base that contains a CR927 3V battery. Base is magnetized for hanging. The non-replaceable LED bulb will burn for at least 4000 hours. Base unscrews to replace battery with #2300 Four 3V CR927 batteries.