British Solomon 1914 KGV Mauritania UPU Archive Specimens

MAURITANIA UPU ARCHIVE RECEIVING AUTHORITY SPECIMENS: 1914-23: KGV values comprising ﾽd, 1d, 2d & 3d all ovptd SPECIMEN. Stamps all in strips of three affixed to portions of ledger page and handstamped with 3-line "SPECIMEN / COLLECTION / MAURITANIE" in red-purple. Sent from the UPU in Berne to the Mauritania Post Office where they were affixed to the ledger page and tied by the Mauritania handstamp. A unique and philatelically important Specimen group.