Stren-Flex® manufactures slings using only the highest quality AMERICAN-MADE webbing and high tensile thread available. Many years of testing and experience go into each sling we manufacture. All Stren-Flex® webbing include red safety core yarns woven into the material that serve as a warning of excessive wear or possible damage to the web. All Stren-Flex® slings are manufactured to meet or exceed current OSHA and A.N.S.I. standards.