FKM fluoroelastomer rubber / 100% waterproof. Interior ventilation channels / Custom aluminium closure pin Designed for Apple Watch Series 6, SE, and all previous versions of Apple Watch Strap is one size fits most, designed for wrist sizes ranging from 150mm to 200mm 95mm length (pin side) and 135mm length (adjustment side) Designed to give your Apple Watch a modern and sleek athletic look for intense workouts and everyday wear. Sport Strap has a lightweight and breathable design which is constructed from a soft, flexible FKM rubber for all-day comfort. A low-profile pin-and-tuck mechanism ensures a secure closure. Workout Ready Sport Strap is built around a minimalist design meant to keep the weight low and ventilation high. Channels in the bottom of the strap and full length adjustment holes increase breathability and flexibility. Pin and Tuck Closure Sport Strap is finished with a custom-designed pin and tuck closure mechanism that is both slim and secure. The aluminum pin latches through the band while the tail end is tucked away neatly against your wrist. High Performance Nomad use FKM on Sport Strap for its excellent balance of comfort and durability. FKM’s natural flexibility allows the strap to easily contour around your wrist and its resistance to oils allows it to quickly wipe clean after a workout. Bold Design A sporty aesthetic and sharp details combine for a distinct, yet understated look unique from any other strap. The black FKM is finished with a subtle microtexture for a classy satin finish.