diameter: Ø6mm  Ø8mm, strong hold backs which enough to hold all the curtain's wide and stop your curtain from getting dirty/frayed. Design: metal polished chrome/Nickel etc, no straps needed, easily holdback or release curtain on both sides of the window, the crystal knob shines in the light and reflects various kinds of brilliant, makes the room more elegant Easy to apply: first put the expansion plug into the holes you drilled in the wall, then press the screw into the expansion plug, at last screw the hook Multiple used as tieback holder or even wall hooks for hanging window curtains shower curtains clothes, cap or the decoration for the room, (Tip: our U-shaped curtain hooks are only available in one color and packaging