A mower unit includes a housing, a pair of cutting blades arranged inside the housing, each of the cutting blades being rotatable about a respective vertical axis supported by the housing, the cutting blades being driven to be rotated in opposite directions, and a baffle arranged generally between rotation regions of the cutting blades to guide air flows generated by the cutting blades. The spiral spring includes at least one folding section, which is formed by two spring legs which are situated essentially in parallel to each other and are connected to each other with the aid of a connecting bar. The user identifier includes a long-range transmitter adapted to transmit an identification signal and a short-range passive component having identification information. The switching device is configured to receive an input voltage at a second terminal of the switching device and provide an output voltage at a third terminal of the switching device. The flex support includes second splines that intermesh with the first splines for transferring torque there between. The probes extract normalization signals from the reference signals, exchange specific ones of the normalization signals, and combine the normalization signals with data signals derived from the transmission signal to form receiver signals.