GHD flat iron hair straightener

I am looking for authentic hair straightener from GHD don't really care what model or color. The only this is I care if it's authentic. The only way I will buy is if seller provides me with serial number of the one I am getting so I can check the authenticity before I buy or bid. So many being sold as real ones knowingly and unknowingly. Just want to save time and money not having to return one if it isn't' real. Thanks