0.45 volts (450 millivolts) is suppose to be the ideal (air:fuel of 14.7:1). Lower voltage is lean, Higher voltage is rich. ALL O2 sensors work the same, it's just the vehicle application that's different. That means it'll cost you less for the same sensor in a mustang than in a MBZ because the quick disconnect plug is different and maybe the size of the hole it's threaded into.
BTW the Fuel:Air adjustment screw is VERY sensitive. Work in fractions of turns of the adjustment tool.