These are a rare, one-of-a-kind 3D holographic space #10 envelopes from the 1980's. 

They features an image of space that is sure to capture the attention of any collector. 

They are unused and in mint never hinged (MNH) condition. 

The denomination of 29 cents and manufactured in the United States. 

They would make a great addition to any space or stamp collection.