When sourcing metal sockets, quality is synonymous with safety. You must prioritize UL, CE, or RoHS certifications to ensure the product meets international electrical safety standards. Key technical indicators include the thickness of the internal copper contact (ideally ≥0.6mm) for optimal conductivity and the fire-retardant rating of the internal plastic housing (UL94-V0). For the exterior, verify if the metal casing is stainless steel or aluminum alloy with anti-corrosion coating to prevent oxidation in humid environments.