When evaluating iron drawer locks, prioritize the material thickness and surface treatment. Ensure the lock body is made of high-strength cold-rolled iron with a thickness of at least 1.2mm to 1.5mm to prevent prying. The surface should be electroplated (nickel, chrome, or zinc) to provide a salt spray test rating of at least 24-48 hours, ensuring corrosion resistance in humid environments. Additionally, verify the cylinder material; while the body is iron, a brass cylinder is preferred for smoother rotation and a longer lifespan of over 50,000 cycles.