The ASTM D1003-2021 standard provides a method for evaluating the transmittance and wide-angle light scattering properties of a planar portion of a basic transparent plastic. This standard includes two test procedures, namely, Procedure A using a haze meter and Procedure B using a spectrophotometer, for the measurement of light transmitance and haze of a material. Materials with a haze value greater than 30% are considered diffuse materials and should be tested in accordance with the E2387 specification. All values are expressed in the International System of Units (SI). This standard does not address all safety concerns associated with use and users need to ensure that appropriate safety, health and environment practices are followed prior to application, taking into account applicable regulatory restrictions.