This bill amends the Controlled Substances Act and the Controlled Substances Import and Export Act to significantly reduce the quantity thresholds for fentanyl and its analogues that trigger specific criminal penalties. For instance, the thresholds for certain offenses are lowered from 400 grams to 20 grams and from 100 grams to 5 grams, while others are reduced from 40 grams to 2 grams and 10 grams to 0.5 grams. These changes also explicitly include scheduled or unscheduled analogues of fentanyl, broadening the scope of substances covered by these stricter penalties. The legislation directs the United States Sentencing Commission to review and amend its guidelines and policy statements to align with these new, lower quantity thresholds for fentanyl offenses. The Commission is granted emergency authority to promulgate these updated guidelines within 120 days of the bill's enactment, ensuring rapid implementation of the revised sentencing framework. Furthermore, the bill mandates enhanced efforts by the United States Postal Service to interdict fentanyl and other synthetic opioids. The Postmaster General is required to increase the availability of chemical screening devices and dedicate appropriate personnel, including scientists, to interpret data from these devices during all operational hours. An appropriation of $9,000,000 is authorized to support these critical interdiction resources.