The document discusses positive displacement flow meters. It provides details about a Chinese manufacturer called JSN Positive Displacement Flow Meter Co., Ltd., including their contact information. It describes positive displacement flow meters as providing precise volumetric flow measurement of liquids for various industries. It lists features of positive displacement flow meters such as their compact design, high accuracy, and ability to measure both high and low viscosity liquids. The document also provides parameter specifications for some of the company's models and details about materials, medium compatibility, output, power supply, accuracy, temperature and pressure specifications.