UL is short for Underwriter Laboratories Inc. in English.

The UL Safety Laboratory is the most authoritative in the United States and the largest private institution engaged in safety testing and identification in the world. It is an independent, not-for-profit, professional organization that conducts experiments for public safety. It uses scientific testing methods to study and determine whether various materials, devices, products, equipment, buildings, etc. are harmful to life and property and the degree of harm; determine, write, and issue corresponding standards and help reduce and prevent damage to life and property. Lost data, while conducting fact-finding business. In short, it is mainly engaged in product safety certification and operating safety certification business, and its ultimate purpose is to obtain products with a fairly safe level for the market, and to contribute to the assurance of personal health and property safety. As far as product safety certification is an effective means to eliminate technical barriers to international trade, UL also plays an active role in promoting the development of international trade.

UL was founded in 1894. In the initial stage, UL mainly relied on the funds provided by the fire insurance department to maintain its operations. It was not until 1916 that UL was completely independent. After nearly a hundred years of development, UL has become a world-renowned certification program for certification and products. UL is governed by a board of directors with representatives from safety experts, government officials, consumers, education, utilities, insurance and standards, and the day-to-day work is handled by the president and vice president. At present, UL has five laboratories in the United States, headquartered in Northbrook Town, north of Chicago, and has corresponding laboratories in Taiwan and Hong Kong respectively.