When discussing restaurant equipment and supplies, NSF and UL are frequently mentioned. Briefly, let's discuss what these two organizations do and what their certifications mean.
NSF International was formerly known as the National Sanitation Foundation. It is a not for profit organization that provides public health and safety safety risk management solutions. Among those solutions, NSF International provides standards development and product certification. Foodservice and restaurant supply products that are certified by NSF undergo and have passed an evaluation to ensure that the product and facility where the product is made meet NSF standards for food safety. NSF standards are generally accepted by government regulatory agencies.
Underwriters Laboratories (UL) is an organization primarily dedicated to product safety. UL develops safety standards dealing with design, electrical, materials, components, and manufacturing. Products that carry a UL certification mark have been found to comply with UL standards for product safety.