Quasi-whiteboard is made of high-quality imported PTFE powder material by 300T high pressure pressing and sintering, which has good diffuse reflection characteristics and is an ideal Lambert reflector. It is suitable for UV-Vis-Near Infrared (200-2500nm) wide spectral band, and can provide more than 90% reflectivity in the whole spectral band, so it is an important component for reflection measurement of non-specular objects. Standard whiteboard is a standard diffuse reflectivity reference for reflectivity measurement, which is suitable for measuring the surface reflectivity of various rough samples (such as ceramics, rough glass, plastics, etc.).