90 Degrees Self-locking Folding Hinge Anti-corrosion Invisible ConnectorSelf lock function: In order to increase safety, these brackets have a spring activated self lock function that can be fixed by locking in the open position. When you are not using a desk or workbench, just click the latch and fold it down to get more space. Adjustable: The elastic hinged table leg frame can be adjusted from 0 degrees to 90 degrees, which can easily adjust the sofa bed, sofa or other furniture. Invisible: The hinge is made of