When you say preamp, I assume you mean you can just plug it into a mixers pre or outboard pre and away you go. They have everything in them that a regular microphone would have. There is a 10' cable attached to each with an XLR jack on the end.The cables are thin enough not to be a bother for you.
The 419 has an extended low end frequency. They are probably better for bari saxes. I have used these ( both 418 and 419 ) for live drums and horns and they have always been fine. For recording I would go with a better setup than any of the little clippers. They are very functional but there are compromises when compared to a quality LDC or quality SDC
( not that these aren't good but hey they aren't SR77s or anything really high end )
Anywhoo. Good luck and like I say make me an offer if you want one.
If you want a picture or something I can send that to you.
Eric