where is the barcode on a ps2?

where is the barcode on a ps2?
I am looking to sell my ps2 silver slimline to ‘play.com’ but there website cant seem to recognize my pin. The number under my barcode is- xx-xxxxxxxx-xxxxxxx do i type it in like that or is there another way.
Please help

Best answer:

try with the – and without
also try without the first 2 , I think they’re unnecessary