The most critical requirement is RoHS (Restriction of Hazardous Substances) compliance, which ensures the scale does not contain lead, mercury, cadmium, or other hazardous materials above regulated levels. Additionally, for the EU market, you must ensure the product carries the CE Mark and complies with the EMC Directive to prevent electromagnetic interference. If the scale is intended for commercial trade (legal-for-trade), it must meet OIML (International Organization of Legal Metrology) standards or NTEP (National Type Evaluation Program) certification for the US market.