US #1890A Imperf Pair - 1981 Mint Imperforate Pair

Issued only in sheet form, this pair is missing perforations on all four sides! The 18¢ rate was in effect for only 7 months, making this 1981 error even more elusive. Add this error pair to your collection while our limited supply lasts! (US #1890A Imp Err Pr)