The Zelus Z Series Fixed Weight Vest uses innovative Z-Fit Soft Iron material that evenly distributes weight to prevent shifting and reduce friction. Its ultra-thin, flat design offers a snug, comfortable fit with more freedom of movement compared to traditional iron sand vests. The ergonomic X-shaped structure and adjustable buckle straps provide secure support for chest sizes from 32.3" to 39.4". Made from soft, wear-resistant spandex fabric with high-visibility reflective strips, it helps you safely and efficiently enhance performance in daily walking, yoga, or strength training.