Authenticity is critical in the used machinery market. Always request the Original Equipment Manufacturer (OEM) serial number and verify it against the brand's database (e.g., Caterpillar, Komatsu, or Sany). Demand a third-party inspection report (CCIC or SGS) that covers the undercarriage wear percentage, hydraulic oil purity, and engine compression. For Shanghai-based stock, it is highly recommended to use live video inspections to check for smoke color during a cold start and fluid leaks under load.