Abstract: Light, which includes a reflector, batteries and a light emitting diode. The light emitting diode and the batteries are hermetically encased between a glass, that also serves as a reflector, and a rear wall of the light. The batteries and the light emitting diode are connected in series with two metallic plates that extend through the rear wall of the light. When the light is mounted on its bracket that in turn is fastened to for instance a bicycle this fastening bracket being metallic contacts the plates closing the circuit and lighting the light emitting diode. Due to the high efficiency of the light emitting diode it will be capable to burn a very long time before the batteries have to be changed and since the light in order to be lighted or unlighted is mounted or demounted possible oxide layers will always be worn away by this motion.