With UL certification by the Underwriters' Laboratories of Canada (UL Canada), an independent, not-for-profit product safety testing and certification organization, Guardian has undergone a thorough and unbiased evaluation.

A ULC or UL mark on a product means that ULC or UL has tested and evaluated representative samples of that product and determined that they meet ULC/UL's requirements.

In addition, products are periodically checked by ULC/UL at the manufacturing facility to make sure they continue to meet ULC and/or UL requirements.