The Tube Tech ME 1A is a mid range equalizer, modeling itself after the Pultec midrange EQ which was one of, if not the first of it's kind. The ME 1A and the ME 1B are both very similar EQ's, and as far I can tell they are interchangeable, although I do not know this for sure since I haven't had the chance to use them side by side. I believe it has XLR connections and will fit into a two space rack.
It isn't very difficult to use the Tube Tech ME 1A, even if you have no experience at all using any of the Pultec style EQ's out there. It's a three band EQ, with the high and low frequency bands being peak bands and the mid being a dip band. Each has gain and a series of fixed frequencies to choose from. A manual shouldn't be necessary, nor have I seen one.
The sound of the Tube Tech ME 1A is outstanding, like everything from Tube-Tech does. It's not the most flexible EQ as it does follow the Pultec model, there's still a lot that you can achieve with it. It's great for guitars and drums especially, but I haven't used it other than that. I've used a lot of gear from Tube Tech and this stands up there in terms of sound quality.
While certainly expensive, the Tube Tech ME 1A is a great addition to anyone's professional studio. While I don't put it up there with the essentials, if you're looking for a Pultec style midrange EQ. Even so, I'd rather have a Tube Tech compressor if I was going to have one thing or another. If you are ever in a studio that has one of these though, you'll definitely want to find something to use it for!