15 mm for wood and 8 mm for copper (you can contact me to adjust the size when placing an order) The bracelet is open, adjustable in size and easy to wear. The wood is natural sandalwood with a slight fragrance! The purchase will give you polished strips, maintenance knowledge, and small woods, each wood has its own characteristics and personality! SinniS loves to play with wood because of his warm texture, ever-changing patterns, meticulous smell, and infinite possibilities! * Note that each grain of wood will be different, but it is definitely of high quality to let you rest assured! * Natural brass will oxidize. If you want to shine, just use the polished strips we gave. It is also very personal to retain his traces of years!