According to UL, the following warning signs may be indicative of a product that does not have UL Listing:
A product whose label does not contain these 4 elements:
The familiar UL symbol (the UL in a circle) or other specific formats authorized by UL
The word “LISTED”
The product identity
A unique control number or serial number assigned by UL
Any product that references UL on the carton or on the product itself but has no company name or address
Any product that references UL on the carton, but not on the product itself
Cheap, low-quality workmanship and/or packaging.
Marks with the letters “UL” side by side instead of staggered, the lack of a control number, or the words “Approved” or “Pending” instead of “LISTED” or “CLASSIFIED”
