1: quality of accessories. The main accessories include handles, pull rods, wheels, box locks, hooks, rings and decorative parts. Require smooth surface and no burr; The metal coating is bright and corrosion-free; The surface coating of plastic-sprayed parts is uniform in color, and there is no leakage and peeling.

2. Overall appearance. Require a straight body and neat teeth; Stand upright and smooth, without unevenness and skew. Leather fabrics shall not be obviously disabled, artificial leather and synthetic leather fabrics shall not have obvious concave and convex marks, and the main parts of textile fabrics shall not have defects such as broken warp, broken weft and yarn jumping.

3. Wear resistance and impact resistance of wheels and tie rods. It is required that under the specified bearing conditions, the qualified products can walk for 8km continuously, and after the excellent products walk for 12km continuously, the wheels can rotate flexibly, the wheel wear is less than 2mm, and the pull rod can be pulled smoothly without deformation or looseness.