Stamps generic certificates from PSE, PSAG, APS, or the Philatelic Foundation are accepted. NOTE "graded" certificates or "encased" items are not accepted. Notes PCGS or PMG opinions are accepted. We guarantee our description, not a specific numeric grade. Proof of the inability of a competent authority to express an opinion is not grounds for return.We use the finest in secure packaging to better protect your items. The item "#C15, 632, 682 ON ZEPPELIN FIRST FLIGHT COVER APRIL 30,1930 HW1910" is in sale since Wednesday, October 26, 2016. This item is in the category "Stamps\United States\Covers\Event Covers\First Flight". The seller is "billsbargainstamps" and is located in Hampton, NH. This item can be shipped worldwide.