CGQ-1 Type Pig Passage Indicator is an indicating instrument used to determine whether the pig passes the installation point during pigging operations of oil and gas pipelines. It can detect, indicate and record the passage of the pig at the installation point of the pipeline. This indicator adopts advanced passive ultrasonic monitoring technology to accurately judge the passage of the pig and the corresponding time point, and transmit relevant information to the display and control unit for visual display and recording.