How to distinguish the quality of ultrasonic dishwashers?

Any product is produced by many manufacturers, but it is difficult for non-professionals to distinguish. Since it is a product, there will be a physical product. It depends on whether the workmanship is fine, the surface treatment is smooth, the welding process, and the delivery of materials. As the saying goes, it costs a penny. There is a big difference between a good ultrasonic vibration head and a poor quality vibration head. The structure, life and stability of a good circuit board and a poor quality circuit board are greatly different. The choice of steel plates is often a poor quality dishwasher. Well, it is sold at a very low price, with no after-sales at all, and great safety risks.