Our lightly sanded spruce blocks are a little shaper on the edges and may have cracks, chips and large knots on the back and sides.  All of our blocks are individually cut and sanded by hand and are therefore there will be minor differences in dimensions of each piece with all sizes being approximate as follows:
Mini square 2.5 x 2.5 x 1.5"
Small square - 3.5 x 3.5 x 1.5"
Mid Rectangle - 4 x 4 x 1.5"
Medium Rectangle - 5.25 x 5.25 x 1.5"
Large Rectangle - 7 x 7 x 1.5"
XL Rectangle - 9 x 9 x 1.5"
XXL Rectangle - 11 x 11 x 1.5"