Secure Whoop 4.0/5.0 Compatibility – Precisely engineered to fit WHOOP 4.0/5.0 Peak/One Straps, maintaining full sensor contact and uninterrupted charging functionality without removal Hypoallergenic Soft Silicone – Skin-friendly, odorless material ensures irritation-free comfort during 24/7 wear, workouts, and sleep tracking Sweatproof & Quick-Dry Design – Withstands intense exercise and moisture exposure while resisting odor buildup for reliable daily use Adjustable Wrists – Size for: S (12.5 cm/4.9 inch~19 cm/7.5 inch), L (17 cm/6.9 inch~22.5 cm/8.9 inch), Please measure your wrist size carefully with a soft ruler before purchasing. Studded buckle provides customizable snugness, preventing slippage during running, swimming, or gym sessions Friendly Service - If you have any questions about the strap, please feel free to contact me, I will provide you with service as soon as possible within 24 hours.