The real question is how many boxes will the fulfilment center place the kg in. If Amazon is anything to go by my money is on 3
I recently ordered a picture frame from Amazon. It came in its packaging box, which was placed in a box by the manufacturer. That box was put in another box by Amazon and shrink wrapped to a large piece of cardboard, which was then put inside yet another box.
On the surface, it seems crazy, but Amazon did manage to get it to me undamaged.