Explanation of icon.
Function name:UL
The term UL stands for Underwriter's Laboratories Incorporated, which is a non-profit organization based in the U.S.A.

The UL executes investigations, researches, and tests in order to probe whether or not materials, products, devices, and systems existing in the world would endanger people, and then establishes safety standards on individual products and releases the related information to the general public.

After the objective product has been safety tested and has passed the test, the UL authorizes designation of the UL certified mark on the product.

In the U.S.A., the majority of the state administration offices require all electrical products on the market to acquire UL certification.

Hence, the UL practically constitutes the product standards in the U.S.A.