Hydraulic tube fittings in the hydraulic pipe system for the prevention of leakage have a non-negligible role. Sleeve fittings have a simple structure, are lightweight, small in size, easy to use, have no welding, and have good pressure resistance, vibration resistance, heat resistance, and reliable sealing. Therefore, it can be used in high-temperature, high-pressure, and vibration pipelines, and is a more ideal connection in the hydraulic system. Domestic and Taiwan-produced ferrule size design is generally consistent, only the Taiwan-produced ferrule bore diameter is small, the double-edged mouth ferrule, a larger diameter than other ferrules, individual specifications, and the domestic ferrule is not interchangeable, but the elastic deformation zone, such as the strength of the cantilever design is better, and greatly improve the resistance to yielding capacity. Double-edged progressive ferrule, more than one prefabricated deformation groove, so that the double-edged mouth tightens more effort, and when the double-edged mouth cut to the appropriate depth, the thrust ring limits the excessive cutting edge into the outer wall of the steel pipe, in order to ensure that the depth of the edge of the mouth cut at the same time, but also to ensure that the elasticity of the zone has a high yielding capacity, the size of the outer diameter of the inner hole than a single-edged mouth is different.