UL is the abbreviation of Underwriter Laboratories Inc. UL Safety Testing Institute is the most authoritative in the United States and the largest non-governmental organization engaged in safety testing and appraisal in the world. It is an independent, not-for-profit, professional organization that conducts experiments for public safety. Different from FCC certification, UL certification is a safety certification. UL is mainly engaged in product safety certification and business safety certification business. Its ultimate goal is to obtain products with a considerable level of safety for the market and contribute to the guarantee of personal health and property safety. . In the United States, UL is a symbol of safety signs for consumers, and globally, UL is one of the most reliable conformity assessment providers for manufacturers.