When you look at Filamet™ under a microscope it's very easy to understand why it works. Quite simply, there is so much metal in it that it's the only thing visible. There is just enough plastic in it to make the metal particles stick together. Filamet™ does not require special hardware, it works in any FDM (the most common) printer on the market today.

An analysis of Filamet™ at various levels of magnification. The background is an electron microscope at 650x