Chongqing Sapp Plastics Co., Ltd. Plastic Containers products are divided into four levels, divided into A grade, B grade, premium, UL premium described as follows: A Grade: Mainly indoor water use savings Class B: mainly kept drinking water storage water, industrial use low-acid, low-alkali used (in the A class based on the increased thickness) Extra: The main industrial use low concentrations of acid and alkali used (in the B-class based on the increased thickness) UL Class: mainly for industrial high concentration of strong acid used (based on the increase in the premium thickness)