SportFlex is ready for sweat, sport, and everything in between. Made from a highly durable soft-touch silicone, it’s waterproof, dirtproof, sweatproof, and stainproof. With an adjustable closure system and ventilation details, it’s built for high-performance – and game for anything. Includes band, hook, clasp, and Fast Link™ slider that makes swapping bands easier than ever. Only compatible with WHOOP® 4.0.