Important notice: a lot of people have been very happy with this product, but, by now, it's clear that this design is right on the edge of what Shapeways can produce to the right quality at this moment. If you buy it, there's a risk of having a less then perfect fit, colors can be different from what you see on the screen, and, depending on how you use your phone as well as the tolerances of the case, it has been reported that the polyamide material can give a sort of polishing/scratching effect on the metal rim of the phone (you can find descriptions online of how to remove these kind of blemishes, but it may still be annoying).
Shapeways has, in my experience, been very good with customer service on this item, so they'll be happy to either return your money or provide a new product if you would be one of the unlucky ones; but it's up to you if you want to run the risk that you may have to go through this process.
4-4 protective case for iPhone 4 - two pack
4-4 is one of the smallest, fully functional protective cases for iPhone 4. For a full description of this item, go here
Order a two-pack of 4-4's in the same color from this page, for only $21.50.