Falcon's are cheap enough new that I don't see the reason to buy used ones, but YMMV. The principle behind them is similar to a still, in that cooling a gas causes the moisture to drop out. Smoke pases through an aluminum tube which is open to the air all around and ribbed to increase surface area. The smoke is cooled and moisture then drops out and collects in a reservoir under the bowl. A later modification was the placement of a small loop of pipecleaner in the reservoir to absorb the liquid. It isn't necessary to the functioning (Falcon's won't gurgle either way, and you can't generate enough suction to suck the slop into your mouth as with traditional pipes) but it does keep it from dripping if you put the pipe in your pocket or pouch.
The straight Falcon's look less bizarre and quirky than the so-called bent one's, and the plain aluminum one's with black bits look less hideous than the colored one's with white bits. The ultimate cool, dry-smoking Falcon is one with a meerschaum bowl, but they are ridiculously overpriced. The rusticated briars are what I recommend. Be gentle screwing them on so you don't crossthread, and only tighten gently. Honking them down will severly shorten the life of the rubber o-ring.
