3 categories of certification from UL (Underwriter Laboratories Inc.)


UL is an US approved testing laboratory which evaluates raw material, component,
products for compliance to specific requirement and offer UL mark to
acceptable products. The UL Mark indicates compliance with certain Standards
only. Compliance with Standards is not a legal requirement or an indication that
legal requirements have been met.
There are several categories of certification – UL Listed, UL Recognized and UL
Classified. UL Recognized is for component level while UL Listed is for standalone
product and means the product is thoroughly tested to UL industry and
safety standards, which includes everything from fire and flame resistance, mechanical
function, and potential electrical hazards. After approved, UL will conduct
quarterly inspection on the product production in the registered factory to
assure the product performance is same as approved standard. Below shows
the UL listed Mark and UL Recognized Mark that applied on Canada and US