[Francis54]

Here's a post about this subject, I found on a US forum :

"Good morning. Yesterday night I visited Michael and Lu in the Weston TTC. Michael brought a box of Nittaku 44 mm orange balls from Vegas. I played with them for a 5 minutes. They are very light, sound horrible, very unpredictable. IMO, the distinction between 38mm and 40mm was far less then 40 mm and this new one. I heard that in China and Japan alot of people already using them. And those countries are the main TT force in the World. So, who knows, maybe in two years they will became a standart."

And apparently, they do have a "44 mm ball" league in Japan!