This is Warm Audio's version of an API 312 microphone preamp. I've had it for about two years and it has always worked flawlessly. It's pretty simple but has a few great features that help when recording a multitude of microphones. It has a HI-Z input for recording an instrument direct, 48V phantom power, a 10db pad, a polarity switch/phase switch and a "tone" button. The tone button lowers the input impedance to 150 ohms. This is excellent for ribbon mics and dynamics (the reason I bought it in the first place.) I soon found out that it worked well with every mic I owned. I bought the WA-412 (four channel version) so off this one goes. I can't say enough about these preamps, especially considering the price.