LED color rendering index (CRI) refers to the ability of the light source to restore the color of the object. The higher the value, the better the color rendering of the light source, and the more truly the color of the object can be restored. Color rendering index (CRI) is evaluated by comparing the color of an object under a light source with the color of an object under a reference light source. For indoor lights, the CRI must be higher than 80, sometimes, it requires CRI>90, for outdoor light, it can be 70.