[Design Idea] Stretchy loop nylon strap with a lightweight structure works with vivosmart 3/4. [New Case Performance] The unique stretchy loop design and distinctive elastic strap create an elegant look and keep your watch snugly on your wrist or arm for an improved workout experience. [Quality Materials] Made of premium nylon; breathable and washable. The soft, comfortable feel is suitable for all-day wear. [Anti-Allergy Design] Holds up well with no signs of wear. Unlike the original silicone band, it is not itchy and is gentle on the skin