Material:These curtain holdbacks are made from premium zinc alloy, this kind of stainless material will not rust and fade easily, can withstand heavy items without deformation.Size: Width of Opening: 21 mm/0.82", Screw Length: 4 x 20 mm/0.16" x 0.78"(D*L), The body of curtain tieback hook size: 50 x 40 x 20 mm/1.96" x 1.57" x0.78"(L*W*H) (not including metal screw), Expansion Tube Size: 6 x 30 mm/0.23" x 1.18"(D*L).Application: Suitable for all kinds of curtain tieback ropes, and the color can match various style curtain holdback ropes no matter simple, classical or gorgeous. Moreover, you can hang these hook on other wall as normal hangers to meet your different needs.Easy to install: If the curtain tie hook is installed on a wooden surface, just screw it in. If the hook is mounted on a concrete wall, please use the drill to make a hole for installing the grey expansion tube on the wall, then install the metal screw into the tube.