If you read the item description on the back of the box carefully, you'll see that this set contains 100 cards, but only 50 designs as there are 2 of each design. The idea is that you can keep one as a collectible and send the other or give the second set as a gift. They are contained in a sturdy cardboard box. If you want to store the box vertically, it'd be wise to put a rubber band around the postcards inside to prevent spills because the box does not have any type of closure, it simply flaps open/shut. The front, back and one side of the box are designed to look like the dust jacket of a book, and the remaining 3 sides are pinstriped golden (not too bright, matches the front color scheme) to look like gilded book edges.
The postcards themselves are on thick paper with a good sheen to them. They don't feel cheap or flimsy, and the photographs are of good quality. They measure 3 and 7/8" wide by 6" long. The backside of each postcard has a brief phrase describing what the front side pictures, for example, the card pictured to the right of the box above says, "A 46-star Victorian crazy quilt flag made out of cotton, silk, velvet, and wool cloth." Some of the cards were beautiful, some stirred my curiosity about the history behind the picture, and some I was indifferent to, which would be expected with a lot this size.
Personally, I wish the postcards had a bit more detail in the descriptions, such as 2-3 sentences rather than 1-2 phrases about the photographs. I would also have liked if the box had a closure of some sort. If you like to send or collect postcards and are Patriotic, this is an interesting lot to have around.