OEKO-TEX 101 Since 2021, all uniform pieces added to the Delta collection are, and will continue to be, certified STANDARD 100 by OEKO-TEX, with the tag to prove it. WHY DO WE TRUST OEKO-TEX® ? The organization represents the highest standards of the textile industry. This is all that they do. The credibility and independence of the OEKO-TEX® certification is widely recognized.