Abstract: An adaptor for fluorescent tubes having contact pins, the adaptor having a fluorescent tube-compatible plug-in socket and an incandescent lamp-compatible screw cap. The adaptor having an external casing. The external casing having the incandescent screw cap. A printed circuit board and an inner casing are both secured to the incandescent lamp-compatible screw cap. The inner casing part having a fluorescent tube compatible plug-in socket and the inner casing having a socket area which has a plurality of contact members. The contact members are electrically connected by bridges on the printed circuit board. A flexible connection of the inner casing to the light fittings is created. The fluorescent tube-compatible plug-in socket receives different shaped caps of the light fittings.