It is mainly used to measure the contact angle of liquid to solid, that is, the wettability of liquid to solid. It can also measure the contact angle of liquid as the external phase. This instrument can measure the contact angle of various liquids to various materials. In the fields of mobile phone manufacturing, glass manufacturing, surface treatment, material research, chemical engineering, semiconductor manufacturing, coating ink, electronic circuit, textile fiber, medical biology and other fields, contact angle measurement has become an important instrument for evaluating surface properties.