Flat plywood board with black and white plastic go stones (7mm high).
Small: 8.5" board has a 9x9 playing area on the front. (No playing area on the back.) 40 black and 40 white stones included.
Medium: 11.5" board has a 13x13 playing area on the front, with a 9x9 area on the back. 90 black and 90 white stones included.
Large: 17.5" board has a 19x19 playing area on the front, with a 13x13 area on the back.180 black and 180 white stones included.