All FCS leashes are designed to offer superior comfort, functionality and dramatically increased strength. Each leash feature innovative design elements and the highest quality materials available. The extensive research and development program at FCS involved rigorous testing to ensure each leash delivers outstanding performance. The FCS 9ft Regular Ankle Essential Leash features 7mm cord thick and can be used in a 2-8 feet wave size. This Leash is made to an extremely high spec, you'll be hard pushed to find a better one on the market.