Thank you for viewing. This is a double-喜平 chain surgical stainless steel (304) bracelet. The clasp is a neat, fold-over type. It's stress-free to put on and take off. Surgical stainless steel, such as 316L, 304, and 202, is a low-allergy material and is used in medical tools like scalpels and scissors, as well as luxury watches. It is a special stainless steel with excellent properties, such as being rust-resistant and resistant to corrosion, oxidation, and heat. Sizes: Wrist circumference (inner diameter) S Size: 15cm M Size: 17cm L Size: 19cm LL Size: 21cm (Example: If your wrist circumference is between 16.5cm and 17.5cm, M size (17cm) would be the appropriate size.) Please specify your size after purchase. (If no size is specified, we will send the M size. Please understand.) The above sizes are not the total length. Chain width: 7mm Material: Surgical stainless steel (304) Please feel free to ask any questions.