UL is the shorthand of an English Underwriters Laboratories (by Underwriter Laboratories Inc.). UL safety test is America's most authoritative, is the boundary of large private institutions engaged in security testing and identification. It is an independent, non-profit, professional organization to do the test for public safety. It uses scientific testing methods to study to determine the extent of a variety of materials, devices, products, equipment, construction of life, property damage and whether the harm; determined to write, issue the appropriate standards and to help reduce and prevent life the property subject to loss of information, while carrying out the facts research business. In short, it is mainly engaged in product safety certification and operating safety to demonstrate business, the ultimate goal is to market the goods with a considerable level of safety, contribute to personal health and property security is guaranteed. As an effective means to eliminate technical barriers to trade, product safety certification, UL, to promote the development of international trade also played an active role.

UL was founded in 1894. The initial stage UL mainly fixed on the fire insurance sector to provide funds to maintain the action. Until 1916, UL was completely self-reliance. After nearly a century of development, UL has become the world well-known certification body, its own set of strict organization and management system, standards development and product certification program. UL is managed by a security expert, the board of trustees composed of representatives of government officials, consumers, education, utilities, insurance and standards department. Day-to-day work is handled by the president, vice president. Currently, UL has five laboratories in the United States, headquartered in Northbrook town north of Chicago, the laboratory set up in Taiwan and Hong Kong respectively.