The black portion of this product is made with thermochromic paint, which changes color from black to green as the temperature rises. Size:Silver 1 & Black： inner diameter 14.5mm.Sleeve: 70mmSilver 2： inner diameter 15.2mmsleeve: 58mm Material: 316 steel, zirconCollection: BLACK GLOVESPackage: Jewelry box*1, Jewelry pouch*1