What they could have said is the + side of the 12v source and the - side of the 12v source. By the way, I notice that the guarantee on the unwired tools unit is 5 yrs.

__________________
Richard Wooldridge
'01 ML320
'82 300D 4.3L V6/T700R4 conversion
'82 380SL, '86 560SL engine/trans. installed
'79 450SL, digital servo update
'75 280C