24.2 x 24.2 cm, 2 cm thick. Compatible sizes are 21.5 x 21.5 cm. This is a very solid and heavy wood. The white canvas is warped, and the red plastic fasteners are broken as shown in the photo. This has been stored at home, so please only purchase if you understand this. Also, due to the size, it will be shipped as a 60-size package. If sold separately, the shipping cost per item will be very high, so we generally do not accept individual sales.