As the title states. Ive had no luck in finding the size for the tamper that came with the machine, google has nothing, Im guessing its about 52/53mm, could anyone confirm?

Im in the market for a new tamper, I know that the pullman ones are custom fit, top notch etc, but at my student budget I really cant afford them, and with my inexperience I cant justify that price yet. For now I just want to try something other than the stock Breville one.

Also I couldnt find the BES860 thread in search, so my bad if it still exists.