Klean Kanteen's bottles, sippy cups, baby bottles, are made of stainless steel. Various of their products have undergone third-party testing and been found to be PFAS-free. While we couldn't find a direct representation that their products are PFAS-free, their FAQs do note that that the steel in their products is unlined. Corporate Commitment: https://www.kleankanteen.com/pages/faq