Clear acrylic blocks which are all 15mm thick. All faces are fully polished. The set comprises 7 blocks in a storage tray as follows:Rectangular: 75mm x 50mm.Semi-circular: 75mm diameter.Triangular: 60° x 60° x 60° 58mm sides.Triangular: 90° x 45° x 45° 75mm hypotenuse.Triangular: 90° x 60° x 30° 75mm hypotenuse.Bi-convex: 75mm long Curved Faces: 100mm radius.Bi-concave: 75mm long Curved Faces: 100mm radius.