2.NSF certification: NSFInternational is an independent third-party certification body, which specializes in evaluating the impact of products on public health, safety and environment. If the use of the sink is related to drinking water, NSF certification is required to ensure that it meets the sanitary standards of drinking water treatment equipment in the United States.
3.UL certification: UL certification is a symbol issued by American UnderwritersLaboratories, indicating that the product has passed UL's safety testing and verification procedures and meets the safety standards of American consumer electronics industry. If the sink is equipped with electrical appliances, UL certification is required to ensure compliance with relevant American safety standards.