This product is a non-standard part customized by customers. It is made of titanium alloy, and its shape is a flat bolt. The product surface is oxidized, and its color is blue yellow green metallic luster. The flat head is perforated, with a maximum diameter of 4mm, a minimum diameter of 1.5mm, and a length of 2.6mm. The size of the flat head is about one fifth of the adult fingernail cover.