When sourcing a used elevator, you must prioritize mechanical integrity and remaining service life. Key specifications include the rated load capacity (kg), rated speed (m/s), and the number of floors/stops. It is essential to verify the traction machine type (geared vs. gearless) and the controller brand compatibility, as proprietary systems from brands like Otis, Schindler, or Kone may require specific software for maintenance. Ensure the guide rails are straight and free of corrosion, and request the original technical drawings and wiring diagrams to facilitate re-installation.