Material: 304 stainless steel, In-kind more beauty than picture. Safe material, harmless to human skin, comfortable to wear, fine polished to make the whole cuffs smooth and rounded. Not easy to fall off. Female: collar inner diameter 11.7cm. Handcuffs inner diameter 5.4cm. Men: collar inner diameter 13.7cm. Handcuffs inner diameter 6cm. Precautions: Please note with safe, sober, non-compulsory as use principle. Note: due to the measurement method and measuring instruments is different, so the size may have a little deviation, this not is description error. International Buyers Please Note. It may be longer. If you can’t receive it for a long time, please contact me first! It’s highly appreciated you. If you are satisfied with our service. Your comment is very important in our business success. If you are dissatisfied with item or have not received the items over 35 days. We will try our best to solve it. We must give you a satisfactory solution. Or 1-3 star good feedback. We will try our best to solve your. Because we believe Anything can be.