Bought these for 2" checkerboard squares that I made.
Good price for the checkers. Came with a cloth storage bag. Nice touch.
The wood species is unknown, but probably something soft and lightweight, like Poplar. Would be better if they were heavier. Next time, I might opt for the heavy $90 stone(?) set.
I did not try to stack these, so I can't comment on how they might interlock.