Darkglass Microtubes B3K 2.0 Bass Distortion Pedal w/ 4 Cables! Attack Switch Blend: Allows to mix exactly how much clean signal you want to mix with the Overdriven. Drive: Sets the amount of gain for this pedal. Grunt Switch: Choose between 3 different Bass boost levels before the gain stages. This interacts with the Drive knob, so you can choose how much of bass you want to saturate Level: Controls the level of the Overdriven Signal.