Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - United States - 1989, 20th UPU Congress, Futuristic Mail Delivery, (45c) multicolored, bottom left corner sheet margin se-tenant block of four, light blue (engraved) color omitted, full OG, NH, VF, C.v. $475, Est. $180-$200 , Scott #C125b