... overlay.Inset Widening manganese steel spring,can disperse force when the hinge closed.Strengthened .spring,thickness 2.5mm,Instead ... of common one thickness 1.5mmStrengthened spring,buffer hinge,bumper hinge.Product adventages:1, Strengthened adjustable screw can ... life.2,Widening manganese steel spring,can disperse force when the hinge closed.Strengthened spring, thickness 2.5mm, Instead ...