In order to meet product safety standards for North America, electrical products such as those sold by OE Electrics must be tested by an OSHA recognized NRTL.
OSHA = Occupations Safety and Health Administration
NRTL = Nationally Recognized Testing Laboratory
NRTLs are independent laboratories that test and certify products to ensure they meet pre-determined safety standards before they can be sold in North America. There are several NRTLs available to test electrical safety of products, but the two most common are UL and ETL (Intertek). All NRTLs test to the same standards, so there is no difference between products that are tested by UL versus ETL.
All OE products sold in the United States and Canada are ETL listed, meaning they have been tested by Intertek and have passed the stringent standards for electrical product safety. Although not part of the testing for the ETL safety mark, the FCC requires a mandatory EMC standard for imports to the USA. FCC47CFRPT15SPTB covers both conducted and radiated emissions. OE “TUF” USB chargers have this required FCC certification.