In the United States, a leather welding apron does not need a certification label to be a legitimate piece of protective equipment, but your workplace might. Start with your employer's policy, then judge the apron on hide, thickness, construction, hardware and fit, match it to the process you actually run, and treat it as the front layer of a complete system. A well-built apron that fits properly and is inspected regularly does more for you than a label on an apron that sits unused on a hook.