This document adopts as final, with changes, proposed amendments to the U.S. Customs and Border Protection (CBP) regulations implementing changes to the drawback regulations, as directed by the Trade Facilitation and Trade Enforcement Act of 2015 (TFTEA). These regulations establish new processes for drawback pursuant to TFTEA, which liberalize the merchandise substitution standard, simplify recordkeeping requirements, extend and standardize timelines for filing drawback claims, and require the electronic filing of drawback claims. This document also provides details with respect to the process required to perfect TFTEA-based claims filed under CBP's Interim Guidance procedures. Further, this document also finalizes regulations clarifying the prohibition on the filing of a substitution drawback claim for internal revenue excise tax in situations where no excise tax was paid upon the substituted merchandise or where the substituted merchandise is the subject of a different claim for refund or drawback of tax.