what does duplex ability propose?

what does duplex ability propose?

That mechanism the printer has a duplex section that will turn the paper automatically so you can print double sided short turning the paper yourself.
it finances the printer can print on both sides of the paper minus any user intervention
its a type of printers, or an Add-on which allow the printer to print on both sides of the page, it will print on first side, then pilfer the paper put money on, print on the next side
Means the printer is skilful of printing on both sides of the page without you have to re-load the page.