The Coal Dust is a true bypass boost based around the classic JFET Mu-amp design. This version has the bias adjusted to be "on the verge of breakup" so that with normal playing the boost is very clean and powerful, but when you really dig in with your pick, you start to get a hint of grit similar to how a tube amp would react. You can make this a completely clean boost, or a dirty/overdriven boost by adjusting the internal trim pot that controls the bias. This makes it a perfect match for a variety of applications. With +20dB of boost, there is plenty of gain for boosting solos or goosing the front end of an amp or pedal for more drive. As an "always on" pedal, it eliminates high end roll off that occurs from long cable runs or multiple pedals. The Coal Dust Boost does a great job of adding strength, clarity and sustain.