Colorful Optical Triple Prism, Triple Triangular Prism Physics Teaching Light Spectrum Crystal DecorationFriendly Tips: 1. Please kindly allow 2-3% difference according to manual measurement.2. Please check the measurement chart carefully before you buy the item. (1 inch = 2.54 cm) 3.Please note that slight color difference should be acceptable due to the light and screen.Thanks.Specification: Material: Glass Occasion: Casual Prism Length: 2 inch / 5cm, 3.9 inch / 10cm, 5.9 inch / 15cm, 7.8 inch / 20cmPackage Contents 1 xPrismPromise If the product has any quality problems, please feel free to contact us, we will help you solve the problem as quickly as possible.