In an advantageous form of construction, the dial has {HEAD ~ at least one magnet}, which by rotation of the dial is guidable along {TAIL ~ the sensors} realized in the form of field probes 
In an advantageous form of construction , the dial has { HEAD ~ at least one magnet } , which by rotation of the dial is guidable along { TAIL ~ the sensors } realized in the form of field probes
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH