In the screw thread of the lamp, where the pot and the upper part of the lamp are connected, there are notches in the screw thread. In the upper part of the lamp, there is a recess in which a metal anchor with a spring is located. When closed, the anchor falls into the notches of the screw thread. The lamp is then locked, because the anchor blocks in the notches of the screw thread. By means of a magnet, the spring is pulled up and the anchor is moved into a different position, pulling it out of the notches. The screw thread is then free of blockage and the lamp can be opened.