4-4.2 Acceptance Based on Supplier Certification When purchasing commercial items, acceptance based on supplier certification, Clause B-5: Certificate of Conformance, may be in the Postal Service’s interest when: Only small losses will be incurred by a defect. The supplier’s reputation or past performance suggests that the products or services will be acceptable and that defective work will be replaced, corrected, or repaired without contest. The supplier’s production processes and procedures are demonstrated to provide quality products that meet or exceed Postal Service requirements. International Standards Organization (ISO) certification and maintenance of certification may be an indicator of quality performance.