surundo Silicone Sport Band for Whoop 4.0

surundo Silicone Sport Band is a soft, breathable, adjustable replacement strap designed to fit Whoop 4.0 trackers comfortably for daily wear and workouts.

This interchangeable band by surundo provides a comfortable, durable alternative to the stock Whoop 4.0 strap. Made from flexible silicone, it resists sweat and water, fastens securely, and adjusts to fit most wrist sizes so you can switch styles or replace a worn band without removing your tracker’s functionality.

How does the surundo band fit different wrist sizes?

The strap comes as one adjustable size that covers 5.9" to 8.26" (150mm–210mm), accommodating a wide range of wrists from teens to adults. Quick adjustment holes and a secure fastening system allow you to get a snug fit that keeps the tracker stable during movement.

• One-size adjustable design fits 150–210mm wrists
• Multiple adjustment holes for precise tension
• Low-profile buckle/loop keeps the band secure

Is the material comfortable and suitable for exercise?

Yes — surundo uses soft, skin-friendly silicone that stays flexible during workouts and dries quickly after exposure to sweat or water. The breathable, lightweight construction minimizes irritation during long wear while remaining durable for frequent activity.

• Soft, skin-friendly silicone for daily comfort
• Quick-dry, washable material for easy care
• Durable and flexible to withstand routine exercise

Will the band work with Whoop 4.0 sensors and charging?

The surundo strap is cut to allow access to the Whoop 4.0 tracker so sensors and charging areas remain reachable. Installation is tool-free with a snap-in design that locks the tracker in place while letting you charge or use the device without removing the band.

• Precise cutouts keep sensors unobstructed
• Tool-free installation and one-click removal
• Allows charging without taking the tracker out

How does this band perform for water and outdoor activities?

The silicone construction is waterproof and resists chlorine, sweat, and light exposure, making it suitable for running, swimming, hiking, and other outdoor pursuits. Its secure fit reduces the chance of the tracker slipping during active motion.

• Waterproof silicone suitable for wet conditions
• Secure fit reduces movement during activity
• Easy to rinse and quick to air dry after use

Who is this for: The surundo Silicone Sport Band is ideal for anyone who owns a Whoop 4.0 tracker and wants a comfortable, sport-ready replacement or color option. It suits athletes, casual exercisers, and daily users who need a breathable, quick-drying strap with reliable fit and easy installation. Note: surundo replacement bands are aftermarket accessories and are not affiliated with or endorsed by WHOOP; compatibility has not been tested by WHOOP.