The Small Wooden Prisms is a et of 21 rectangular blocks, size 1 cm x 1 cm x 20 cm, in a natural wood finish.  The prisms are used to calculate the volume of the Broad Stair blocks (sold separately). Includes storage box with lid.

Learn more about how to use the Thin Prisms together with the Broad Stair in our blog post, "How to use the Montessori Broad Stair".