Thank you for viewing! Direct purchase without comments is OK! Material: White copper (an alloy based on copper) Size: 11mm * The screw post diameter of the concho is approximately 4.6mm. It is said that a 4mm hole size is suitable. We do not have expert knowledge, so we are referring to AI information. Please make the final decision yourself. Please be aware of color unevenness, scratches, etc. Due to amateur measurements, there may be detailed errors. The color of the actual product may differ from the photo depending on the shooting environment. Delivery will be in simple packaging. In addition, we have many other items for sale, such as brass carabiners, wallet chains, vintage-style items, stainless steel products, and brass keychains. Please take a look at them as well. Thank you for viewing!