1. The end of the nail must be round and smooth, and should not be higher than the surface of the assembly. The rivet should be firm and loose.
2. The hardware shall be assembled reliably, and there shall be no looseness or jamming at the sliding position that may affect the service performance.
3. Lock, window lock hook and bolt shall be flexible, complete in appearance, without obvious defects affecting the appearance.
4. There should be no crack, burr, mechanical damage on the outer wheel Gallery, and the coating should not fall off.
