This Relational Solids productis designed to teach students the relationship of shapes & also dimensions concept. Use liquids to fill them too.All measuring a relationship to 5cm bases. It is important for children to understand the concept of volume relationships. This set of 17 relational Geo solids contains: Prisms: 1 x Hexagonal, 2 x Triangular, 1 x Pentagonal, 2 x Rectangular Pyramids: 1 x Triangular, 1 x Square, 1 x Pentagonal, 1 x Hexagonal, 2 x Cubes, 2 x Cylinders, 1 x Cone, 1 x Sphere and 1 x Hemisphere.