tx charge lead

[pdcnc]

hi all
what lead can i use to charge futaba 6ex from hobbico mk2 field charger not sure which way polarity should be on plug for tx

[Chippy]

On my futaba lead the positive(+) is in the center and the negative(-)is the outer and the leads are coloured red(+) and black(-) and just plug in with some bananna plugs.