Made of silicone, it is non-toxic, non-cracking, long service life and non-irritating to the skin Closed-loop wristband, bright color, good feel and comfortable to wear Frequency:13.56MHz; Chip: Fudan Waterproof, moisture proof, shockproof, high temperature resistant Widely used in swimming pools, bathing centers, water parks, cooling warehouses, waterproof inspections, field operations, etc.