1.Product damage caused by transportation
2.Performance of products on the basis of thermal expansion and contraction, due to user wrongly installation, vandalism, misuse and improper maintenance caused by discoloration, stain, deformation and other quality problems
3.Product quality problems caused by improper operation
4.Subtle chromatism caused by long-term usage, discoloration, deformation, small cracks, but does not affect the normal usag
5.Other quality issues caused by not complying with the WPC performance.