1.Adopting double-spring design,opening lightly and closing smoothly,prolonging service life. 2. Inside pressure reducing value:using to prevent the destruction of the floor spring or oil leakage on occasions that the door is closed by strong pressure or wind force. 3.General design,suitable for left or right hand to open the door in single and both sides. 4.Use low temperature frostbite hydraulic oil,ensuring the normal door-closing speed when the temperature is forty degree below zero degree. 5.For cement container,6mm adjustable in length,5mm in width and 10mm in length,which is convient for assembling. 6.Super thin designed,enable it convenient to installed in district with special demands.