Size (thickness): 12-10G (due to irregular shape) Inner diameter: Approximately 1.6cm Shape: Bone/Bamboo Material: Surgical stainless steel I think it's an unusual design, like a delicate ring, with an irregular shape. I will disinfect with alcohol and wipe it down again before shipping. Please consider purchasing soon, as I may suddenly remove the listing. For those who understand used clothing, thank you.