... AQualified1Smoothness & CleanessWhite sheet surface,fiber isaverage,no gravel and metalicpowder,even sheet texture ≤1 formechanical impurity(≥0.5mm ... (≥2mm) White sheetsurface,fiber isaverage,no graveland metalic powder,allow0.5mm mechanicalImpurity.2Tensile Strength,(Mpa)≥24.020.718 ... outside, on the barrel, there should be attached label and quality certificate, on which there are brand, trademark, ...