This Cigar lighter lead is a curly cable which allows all vehicle servers to be powered from the vehicle's cigar/cigarette lighter socket . This is useful in the case that the diagnostic lead / socket in use does not supply a power feed.
It should be noted that the cigar/cigarette socket supply may be supplied via the ignition switch, but if this is not connected or does not work for any other reason then a using the battery clip adaptor with the Cigar lighter lead allows a direct connection. It also adds approximately 1.5meters of cable.