The invention relates to a three-pole adapter plug, comprising, on a first side, a safety plug with two pins and two earth conductors, in particular a hybrid plug according to the standard CEE 77 with an additional contact sleeve for a FR earth pin. The lens may further include a substrate for fixing the core layer on a surface thereof, the substrate having tabular shape being made of a light-transmitting material. In addition, this cleaning liquid can be stably supplied at low cost. The state of the power state machine can thereby be controlled and therefore the parameters of the associated processorcore, i.