Features: brand new and high quality High transparency and good refraction, more suitable for your needs. Environmental friendly, non toxic, smooth edges do not hurt your hands. A nice choice to be sent as gifts for students, teachers, professors and friends. Full of the sense of science, attracts children's attention, and makes children like science. 5 sizes to choose from, contains gift boxes, suitable for a wider range of crowd or scenes, provide you more choices. Specifications: Material: Glass Size: Approx. 30x30x50 mm 1.81x1.81x1.97 inch/30x30x100 mm 1.18x1.18x3.94 inch/30x30x150 mm 1.18x1.18x5.91 inch/30x30x200 mm 1.18x1.18x7.87 inch/25x25x80 mm/1.18x1.18x3.15 inch Package Includes: 1 Piece Triangular Prism note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.