(a)(1) Until the effective date identified by the Postal Service in a future FEDERALREGISTERdocument, a 1-day (overnight) service standard is applied to intra-Sectional Center Facility (SCF) domestic First-Class Mail？pieces properly accepted before the day-zero Critical Entry Time (CET), except for mail between Puerto Rico and the U.S. Virgin Islands, mail between American Samoa and Hawaii, and mail destined to the following 3- digit ZIP Code areas in Alaska (or designated portions thereof): 995 (5-digit ZIP Codes 99540 through 99599), 996, 997, 998, and 999.
CFR 39-121.1-2014 history
2014CFR 39-121.1-2014 Postal Service. Part121:Service standards for market-dominant mail product. Section121.1:First-class mail.