This machine is manufactured according to ASTM D1148, and this standard specifies the test method for the degree of yellowing resistance of materials such as rubber and white products to approximate sunlight and ultraviolet light irradiation; The function of this machine is to simulate the ultraviolet radiation and heat of sunlight, and to observe the degree of yellowing resistance of the test piece after being exposed to ultraviolet radiation and temperature inside the machine for a period of time. There are two testing methods: A (sunlight irradiation) and B (ultraviolet irradiation), and the grade of yellowing is determined by using the stained gray mark as a reference. Suitable for aging resistance testing of shoe materials, textiles, and daily necessities products.