The Furman HDS-16 is a headphone cue system designed for use in professional recording studios. The box serves as a base for Furman HRM-16 headphone mixing boxes, as you send your signals to these boxes from the HDS-16. As far as connections go, the HDS-16 has a lot of them. It has eight mono 1/4" TRS inputs and four sets of stereo pairs in the form of 1/4" inputs. It then has another set of the same connections, but this time in the form TT connections, so you can plug it easily into your patch bay. The box also has a talkback section on the front panel. In the back there are six output connections for sending it to the HRM-16 headphone boxes. It is indeed rack mountable in a traditional rack casing. The HDS-16 system is overall one that is very simple to use, as it isn't cluttered up with any unnecessary features and only the ones vital for getting the job done. It is built very well, as I think it is something that should last a very long time when treated right. Something like this most likely isn't necessary for a home studio owner, but is absolutely necessary in a professional studio. I'm definitely a fan of the HRM-16 boxes that go along with it as well, as they are nicely designed and easy to use as well. I've never found that I didn't have enough connections either, as the HDS-16 is definitely fully equipped for most applications. The price is about right for both the HDS-16 and HRM-16 combination, but still makes it only accessible for professional studios or perhaps larger home studios where something like this might be necessary. Besides the Mytek Private Q system, the Furman HDS-16 is probably the best one out there for the price.