In America’s voluntary certification system, you are free to choose which third-party certifier you will use for product certification. State and municipal regulations may specify that the certification organization must be a Nationally Recognized Testing Laboratory (NRTL), but they do not specify which NRTL or which mark to use. CSA International is a Nationally Recognized Testing Laboratory, accepted throughout America by federal, state and local authorities, and so the CSA mark is always a wise choice.