The 40 mm Midnight Black Nike Sport Loop is a lightweight, breathable nylon band woven with reflective yarn for subtle visibility in low light. Featuring a double-layer construction, the skin-facing dense loops cushion your wrist and wick away moisture. Its hook-and-loop closure includes a pull tab branded with the Nike Run Swoosh for quick adjustment mid-run or on the go. Crafted from recycled polyester, spandex, and 80% recycled nylon, the band balances performance with sustainability. It fits most wrists and is compatible with Apple Watch sizes 38 mm, 40 mm, and 41 mm.