10mm, and the length that can accommodate hooks is > 55mm, achieving the best effect. Please refer to detail image; PLEASE CONFIRM Make,sure that the adjusting hook is compatible with the track/roman pole.【High-Quality Material】Pinch pleat curtain hooks are made of high-quality plastic, not easy to oxidation, durable, not easy to break or deform, colorless and tasteless, has been polished and has no burr on the surface, light and easy to carry or store.【Main Application】Plastic pleated curtain hooks are widely used for light window curtain, door curtain and shower Curtain. Let the curtains hang freely, making it easier to move and easier to push.（Applicable to curtain hooks (such as perforated type, Korean pleat type, four-pronged hook type, etc.）【Easy to Use and DIY Install】Curtain pleat hooks can be easily installed and hung on curtain without other tools or any instruction. The hook is detachable, light and strong. It is convenient for you to DIY hang and install your curtains, saving you time and energy." />