HH49X micro resistance slow closing butterfly check valve is used in the drainage pipeline of clean water, sewage, seawater and other media, which can not only prevent the backflow of media, but also effectively limit the destructive water hammer to ensure the safety of pipeline use. It has the characteristics of novel structure, small volume, light weight, small fluid resistance, reliable sealing, stable opening and closing, wear resistance, long service life, oil pressure and slow closing are not affected by the medium, and good energy-saving effect.