The Shure A15AS Attenuator is a simple connector pad that goes in between your microphone and your console/preamp/audio interface. It has a few different settings, with a switch for choosing between 15, 20, and 25 db attenuation levels. While certainly not always a necessary piece to use, you also don't want to be stuck without one when you might need one. Most microphone preamplifiers will be able to adjust and adapt to most microphones, but sometimes a microphone has too hot of a level to be turned down using only the preamp and that's when you'll needing something like the A15AS Attenuator. Having three different settings is really a great thing and is what sets this one apart from the rest. Many attenuators will only have a single setting, which might be okay, but having a few different settings will simply insure that you're going to be ready for just about anything when it comes to an all in one attenuator. Shure is more than a reliable company, as I've used all sorts of products made by them and can't recall any bad experiences with them if there have been any at all. While compatibility really isn't really an issue with these types of things, I guess it's kind of comforting if you're using a microphone and an attenuator from the same brand, as you know that they're coming from the same place and should work well together. The price of the Shure A15AS Attenuator is a bit more expensive than most other pads out there, but not by too much at all. If you're a professional looking for an attenuator I'd definitely suggest going with this one, but if you're a home studio owner you can probably get away with a cheaper one if you don't think you'll be using it all that often.