The Bamboo table tops are 25 millimeters thick. The holes are 20 millimeters. A lot of other brands use these 20 mm holes. It looks like it is a kind of standard.

Note that the tables are hanging freely on two supports. There are no steel or other objects on all sides. (Except there where the hinges are). This means that there is no danger for you saw blade (Circular or Jig-saw) when you hit (by accident) the tables with it. The reason the tables are quite thick is because a lot of professionals just saw in them. If your saw is adjusted nicely there is no problem, you only get "saw stripes" in the tables.