100pcs Professional Blue Light Blocking Screen Protector Card Test Light Test Uv Glasses Test Card Accessories for HomeOOTDTYechs: the stronger the blue light, the deeper the discoloration.1000pcs per pack to meet different requirements. A simple structure that provides convenience and ease of use. Can be used for a long time, suits for personal use at home or shop. Designed to test blue glasses, use the blue light emitter to glow on the white square below. Specification: Material: PVC Measurement: About 39x6 1mm/1.5x2.4 inchPackage Included: 100x Blue Test CardNote: please allow 1-3cm error due to manual measurement. Pls make sure you don't mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item.