CULus is a certification mark given to products that have been tested and meet the requirements of Underwriters Laboratories. CULus stands for “Underwriters Laboratories Inc. Certified for the United States and Canada.” The mark indicates that the product has been evaluated by UL and meets the applicable safety standards. To apply for CULus certification, manufacturers must submit a product to UL for testing. If the product passes the tests, UL will issue a certificate of compliance.