"Our Zouaves, Col. Birney, Col. Baxter, and Col. Goslam", overall patriotic design, franked with 3c rose, cancelled with boxed PAID, adjacent red Boston c.d.s. in red (11 May), to Philadelphia, Upham imprint on reverse (Weiss PM-289a, Walcott L-558U), a few trivial marks to address, a beautiful cover, with clear 2023 Philatelic Foundation certificate; ex Walcott.