The two brands of vehicle window film were compared the thickness by using a micrometer. The thickness of both types of car window film samples was determined to be 0.007 millimeters. The transmittance of the sample window films was measured using a Shimadzu UV-3600 spectrophotometer. From the experiment, it was determined that for the visible light range, A and B brands of vehicle window film filter visible light with approximately the same efficiency. In addition, it was determined that the transmittance of brand A and brand B, in the near-infrared (NIR) band was between 60-70% and 10-20%, respectively. As a result, brand B can absorb more, resulting in a low transmittance. Meanwhile, brand B may offer greater solar heat protection than brand A.