Yes, the limit is 10mm. In Europe also known as the Wolf endpin ball.
But mine got some rubber off due to the rough street surface.
Since I dislike to take it off and replace it with a normal rubber foot, I might buy another one and use the new one indoors and the old one when I'm outside. Unfortunately they don't sell replacement rubber balls without the metal mounting part, so you have to buy the whole thing again when the rubber gets hard after many years or if the rubber was scrape off the ball due to hard scratching on the streets (maybe it happened by turning the bass in place on mine).