?? Weight: 4 gram/piece. ?? Size: External Diameter: 4 cm(1.58 inch), Internal Diameter: 2 cm(0.8 inch), Height: 1 cm(0.4 inch), Coil Thickness: 0.25 cm(0.1 inch). Stretch Length: 30 cm(12 inch), ?? Material: TPU: Thermoplastic Polyurethanes, A kind of Polymer Material Between Rubber and Plastic, Safe and Harmless to Human Body. ?? Notice: Do Not W..