Ok, let's do Trem Basics 101.
-Tremolo is an incorrect musical term. What the device does is actually vibrato. You can thank Leo Fender for the goof. Now we're stuck with it. :-)
-There are 2 different tremolo system setups:
1. Dive Only.
2. Full Floating
-With Dive Only, you will only be able to lower the pitch of the notes (dive bomb).
-With Full Floating, you will be able to lower *and* raise the pitch of the notes.
-A Dive Only tremolo system is where the underside of the main trem plate rests on the top of the body. The trem can only be moved in one direction.
-A Full Floating tremolo system has part of the guitar body cut out underneath the bottom of the main trem plate. This allows it to be "pulled back", or pitch to be raised.
-There are advantages and disadvantages to both systems. Most players tend to stick with one or the other, depending on their playing style.
Different guitar makers utilize different systems. As Dr. Evil...oops...Ansil asked, we'll need to know what kind of guitar and what kind of tremolo system. A pic or two wouldn't hurt; either of your particular guitar, or of one you find online. Please don't post pics of Kerry's guitar (he scares me, a lot).
We can continue after we get more info.
You have your assignment.
Class dismissed.
Slain- correct, but there are a few other things you need to consider as well: is the trem able to travel as far as necessary (without saddles slipping/hindering the strings), pickup height adjustability, etc.
LoveKraft- my favorite trem system in the whole world actually *does* have a battery hookup.