Red-Core Slings are made with impregnated nylon webbing specially designed for slings. Red-Core Slings have red markers included in the inner lifting yarns. These red "Safety Alert" markers are immediately visible if the sling is damaged enough to expose the inner lifting yarns.Red-Core Nylon Slings are tagged with a heat-imprinted sewn-on tag and meet or exceed all present OSHA and ASME B30.9 Standards.