The Urei / JBL 527 A is a simple graphic equalizer that consists of 27 bands and is best suited for use in the recording studio. I've only used it in the studio, and I don't think that I'd recommend using it elsewhere since it isn't your typical cheap graphic equalizer at all. This is an all analog piece of equipment, the types of connections of which I do not know. It was connected to the patch bay of the recording studio where I used it, so there was no need to make any connections in the back of it. This is indeed a rack mountable piece of gear that will take up two spaces.
If you are at all familiar with graphic equalizers, you'll be able to understand the Urei / JBL 527 A without hesitation. Either way, graphic EQ's are really very simple and self explanatory anyway. The 527 A has 27 bands of sliders, ranging from 40 Hz on the low end to 16 kHz on the high end. It also has a gain knob for setting your output level, but besides that there aren't any other parameters. Because of this extremely simple make up, a manual isn't necessary.
The frequency selection of the bands on the Urei / JBL 527 A makes it a great graphic EQ with a lot of room for getting the proper equalization done. I will always choose a parametric EQ over a graphic one, but the 527 A is a lot more versatile than most graphic equalizers as it has more bands than most out there. It has a very clean tone quality that doesn't color your sound at all beyond the EQ moves that you'll make. I've used the it on electric guitar, drums, and bass guitar thus far in my time using it, but I definitely think that it will work well for any application.
The Urei / JBL 527 A isn't the most popular piece of gear made by Urei, as it definitely seems like these are hard to find, but if you do get a chance to use one I think you'll like what you hear for sure. I'll pretty much always recommend going with a parametric equalizer over a graphic one, but this is definitely an exception when it comes to the 527 A as it's really as good as most equalizers out there and can do the job just as well for sure. Urei makes top notch gear for professional engineers, and the 527 A graphic EQ is definitely no exception.