Not saying that I know anyone foolish enough to loose the ball bearing for the switch or who ordered several different sizes attempting to find the right one, but if I did, he would tell you that it's a 2mm bearing. I couldn't find this posted anywhere, so I thought I'd put it up here for posterity. There is a lifetime supply for $5 here:
250 2mm Diameter Chrome Steel Bearing Balls G25 | eBay
The accessory kit direct from Atmizoo is priced quite reasonably and includes a few of them along with some o-rings, springs and such, but they have a flat rate 19 Euros for shipping, so it ends up being around $30 when all I was really after was a single bearing.
250 2mm Diameter Chrome Steel Bearing Balls G25 | eBay
The accessory kit direct from Atmizoo is priced quite reasonably and includes a few of them along with some o-rings, springs and such, but they have a flat rate 19 Euros for shipping, so it ends up being around $30 when all I was really after was a single bearing.