USPS US Flag 2016 Forever Stamps Book of 20 U.S. Flag USPS Forever Stamps - Book of 20 - 2016 Release Forever stamps are always equal to the USPS first-class one ounce letter rate First class stamps can be used towards total postage of any USPS mailing Easy to use Peel-n-Stick. Self Adhesive no licking. Issue Date: January 29, 2016. Art Director/Designer: Terrence W. McCaffrey, Greg Breeding