When sourcing heavy-duty trolleys, the most critical factor is the Load Capacity, which typically ranges from 500kg to over 2,000kg. You must verify the Material Grade, prioritizing reinforced carbon steel or industrial-grade aluminum with a powder-coated or galvanized finish to prevent corrosion. Additionally, pay close attention to the Caster Specifications; high-quality trolleys should use heavy-duty polyurethane (PU) or solid rubber wheels with precision ball bearings and integrated braking systems to ensure maneuverability and safety under full load.