1. This product is suitable for liquid and gas medium pipelines and equipment to prevent medium reverse flow. It is installed on horizontal pipelines. 2. The valve is an automatic product, which is opened in the downstream and closed in the upstream. 3. Small flow resistance of circular channel. 4. H44X series products are designed with the technology of valve clack wrapping rubber, so they have the advantages of high elasticity, corrosion resistance, good sealing performance, reduced wear, e