This surfboard leash cord uses DIAMOND FLEX material and is designed for waves from 1' to 6'. - Model: 6 COMP - Feature: DIAMOND FLEX - Suitable wave size: Suitable for waves from knee-high to head-and-a-half high in Japan, but for powerful waves, it's best to use a leash cord with a thicker diameter if the waves are larger to prevent breakage. Thank you for viewing.