... surface,high purity: no blackspot, no obvious scratches, no air bubbles ect.b) Polished eage without obvious chipAlu. quality control:a)Shine ... smooth profile: no Mechanical trace,no distortion,no scratches ect.b)Alu, thickness should be correct.c)Past the salt spraying ... ,Sliding, Pivot & Hinge typeFactory: Local in Foshan, 100 worker,18000 square meter Bathroom shower screen JK2809