The Baggs 'Hex' transducer setup consists of six USTs, each sealed into a seperate saddle piece made of brass. They have tiny setscrews on the bottom, so you can adjust the height individually, and each one has it's own lead out. They fit into a standard saddle slot, but you need to have a certain amount of 'meat' at the bottom for it to work right.
I've installed a few of these: one of my customers, Ken Bonfield, really likes them. One big up side is that you won't have a dead or weak string, so long as the break angle is about the same across the saddle.
Installation can be a bit of a pain. Aside from the six holes to drill in the top you have to do something with all of the leads. Normally they are soldered to a small printed circuit board, that comes wih the set, so that everything is ganged into a single output wire to the pre-amp. They include a couple of small surface-mount capacitors to add to the board, in case the output of the pickup is too hot. The wires are small shielded single-conductor ones, and they include a piece of copper foil with a sticky back to put over the board to shield it, as well. I would not try one of these if you're not at least reasonably good with a small soldering iron. It's a bit of a deal to fish the wires out through the soundhole and do the soldering without messing up the guitar; a piece of cardboard over everything is a must. Getting the wirs to dress out neatly inside the guitar is also a nice trick. A systematic approach, and some patience, go a long way.
These do seem to work nicely, though. If you want to know more about how to use them; things like the best pre-amp and so on, go to Ken's website, or drop him an e-mail:
bonfieldk@gmail.comwww.kenbonfield.com www.artistryoftheguitar.com