[Size]Inner Diameter: 5mm / 0.2"; Thickness: 1.2mm / 0.05"; Package Included: 50 x O-rings||[Material]O-rings made of iron materials, electroplating surface treatment, non-welded, works fine, and with many functions.||[Advantages]Sturdy, good for DIY purposes. O ring buckle is both component and ornament for shoes, handbags, luggage straps.||[Applications]They are suitable for making belts, clothes, luggage belts, and backpacks etc.||[Note]The breaking strength of the product can be varied with respect to individual applications. It can't be open unless by tools.