What is the polarity of the supply cable in a DC to AC Inverter?

I have a Teleadapt DC to AC car power inverter, model number TANOTEAC90A. It converts 12V car supply to 120V AC for my computer charger. The 12V plug end was damaged and unfortunately has been cut off and thrown out. To repair this, I have another car adapter plug with wires attached. I want to connect this to the inverter.

I have two questions. The inverter 12V supply wires are colour coded red and white. Which is the positive, red or white?

Secondly, what fuse should I use in the new plug? I'm guessing 8 or 10 amps is OK.