Package include: 16pcs 4 sizes, 4pcs each sizeSize: Outer Diameter: 20 mm (0.79 inches) thickness 3.8mm, 25 mm (0.98 inches) thickness 4mm, 27 mm (1.06 inches) thickness 4mm, 33 mm (1.30 inches) thickness 4mm. Color: SilverMaterial: Zinc AlloyOur spring O rings are made of good zinc alloy material, They are light weight and high strength and widely used, which is good for your daily life.① Come with 16 pcs and 4 sizes, they are enough for your different needs.② They are made of high-quality zinc alloy, light weight, high strength and durable.③ They are anti-rust, anti-corrosion, can be used for a long time.④ They are designed with built-in spring, easy to operate.⑤ They are good DIY accessories, suitable for key chains, bag, purse, handbag and so on.⑥ They can be the accessories used for indoor or outdoor activity.