Optimal Comfort and Performance: Experience the ultimate in comfort and functionality with our HydroKnit Wrist Band, specifically designed for Whoop 4.0. This replacement strap features a unique U-shaped design that ensures a secure fit while maintaining full sensor functionality. Advanced Material: Crafted from high-quality HydroKnit fabric, our wrist band excels in fast-drying and sweat-wicking capabilities, keeping you dry and comfortable during intense workouts and daily activities. Easy Maintenance: The material is easy to clean and maintains its form and functionality even after repeated use, making it an ideal choice for everyday wear. Note:due to the different production batches, the physical objects are slightly different, which does not affect the use. Colour:Blue Material:HydroKnit Package Contents: 1 * Waterproof and quick-drying Wrist Band Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.