This US stamp set features 4 stamps commemorating the 20th Universal Postal Congress, with a denomination of 25 cents and a year of issue of 1988. The stamps are from the United States. They are of used quality and have a machine cancel cancellation type. The stamps are off paper and uncertified. The set includes stamps #2434-2437 and is a great addition to any collection or lot of stamps. The stamps are ungraded. The features of this set include being off paper, and the topic is postal. The country/region of manufacture is the United States. This is a great set for any stamp collector or enthusiast.