It started with a crowdfunding project last August. Now, nine months later, the world's first 3-D printed gun is here. Announced via Forbes exclusive on Friday, the design, called the Liberator, is now available for download.

Here are what the parts look like:

The Liberator 3D Printed Gun, disassembled: The only vital metal component? A nail, used as a firing pin.  Defense Distributed

Before making a complete 3-D printed gun, Defense Distributed tested a printed part of an assault rifle. In December, the test version fired 6 shots (out of a magazine of 10) before breaking. Defense Distributed have been refining their technology since, adapting to the needs of the material--by curving the plastic wherever possible to strengthen it against stress that broke square parts and thickening the plastic so that it better absorbs force. A later design, demonstrated in February, fired 600 rounds just fine. With a firearms manufacturing license in March, Defense Distributed was legally in the clear to make a 3-D printed gun they could sell.