Petex-15 is a Contractor Grade Synthetic Underlayment. Petex-15 is a direct replacement for #15 conventional roofing felt that provides greater installation efficiency and is tear resistant. Unlike other #15 conventional felt replacements that are manufactured in China or India, Petex-15 is proudly Made In the USA. Petex-15 Contractor Grade Synthetic Underlayment provides the best solution for shingle applications that require an highly efficient application and a job that is price paramount.