Package content:20 0pcs D-rings and screws Material: galvanized surface metal material, sturdy and durable, corrosion resistant, high strength and long service life. They can be used for hanging photos, paintings, clocks, decorations, lights, kitchen utensils or even clothes. Reduce damage to walls:After removing the professional hanging kit, there are only small holes left for nails and can be easily covered with paint. Tiny invisible nails can be reused. All you have to do is place the hook on the wall and use a hammer to drive the nail into the wall. The curved upper part of the hooks protects your fingers from injury. You can use a drill to make a hole first if you have trouble driving the nail into the wall. Specification: Material: iron Hanging part size: please refer to the picture 'image Screw size: please refer to the image Color black How to install: Place the screws in the groove of the image bracket. just use Phillips screws on the back of the wood. the screw is small but easy to install. Note: With small screws, keep away from children and avoid swallowing