Stamps described with faults are NOT returnable. Stamps generic certificates from The Philatelic Foundation, PSE, or the APS are accepted. NOTE "graded" certificates or "encased" items are not accepted.Proof of the inability of a competent authority to express an opinion is not grounds for return. The item "#C14-C15 ON FIRST FLIGHT ZEPPELIN COVER WITH CERT - XF - HW2293" is in sale since Thursday, February 9, 2017. This item is in the category "Stamps\United States\Covers\Event Covers\First Flight". The seller is "billsbargainstamps" and is located in New Milford, New Jersey. This item can be shipped worldwide.