I have 2 RG550 's that I bought used, each one has a different bridge, and I'm hoping that one of them is a LO PRO instead of the LO TRS, but I don't know the difference.
The major difference that I can see, has to do with where the allen wrench screws that push the block up against the end of the string to hold it in place. My RG550DY has the screws up on top of the bridge, and I like this. This bridge looks just like the one on my Jem FP, and for a number of reasons, to me it's just better. But the other RG550 I have, has those allen screws on the back of the bridge, under the fine tuners, and I hate it. I went to a few music stores this weekend and looked at a few RG's and they all seem to have the allen screws under the fine tuners.
SO.....do you think my RG550DY has a LO PRO and my white RG550 has a LO TRS??? Why does the bridge on my DY look just like the bridge on my FP?

The first RG got a lo-pro, the other rg has an edge trem.

Take a look here:
http://jemsite.com/axes/htm_features/trems.htm

THAT'S IT!!! I hate it when I'm guilty of not looking on the rest of the site for this stuff. I couldn't find those pictures, but that link is exactly what I needed to see. The DY has a LO PRO!!! Very cool!!!! Thanks!

I have to ask . . .

Why do you hate it?

As far as how they perform, the Edge and the Lo-Pro Edge feel pretty much the same, the only thing I could see being a problem with the Edge is if you play with your hand all the way back where the fine tuners are, they are more forward on the Edge's "Whale Tail" design.

I was going to swap both my Edges for Lo-Pros, but decided not to after playing a Low-Pro, just didn't feel any different and I decided it wasn't worth spending all that cash on them, I could buy another guitar, almost, for the amount of two Lo-Pros.

They both stay in tune, they both have the same tone (consistant casting assumed) and they both (for me anyway) take about the same time to restring (I handle a few of my friends' guitars and a couple have Lo-Pros) . . .

Just curious as to your reasons for hating the original Edge.

Mic

Just to help in the future, the easiest way for me to identify an Ibanez bridge is to look for the knife edge inserts. I've never seen any Floyd aside from the Edges that have replaceable knife edges. What a great design idea too! But it's great for these "mystery RG's" and the pictures are vague, just try to spot the knife edge inserts...

Either way the Edge and the Lo Pro Edge you have are basically the same tremolo, the only difference is the location of hte finetuners and saddle lock screws. Both are great trems, but which you prefer is personal preference entirely.