The classic RAT tone with two new circuits enabling a new sound. The standard that all other distortion devices are measured against. Heard on thousands of recordings, it has helped define the sound of the past three decade's most influential bands. Clipping Section: Switchable between stock silicon clipping, as in the classic Rat, and a mosfet/germanium clipping section, which is entirely new to the Rat line. The mosfet clipping section gives you subtle scoop and smoothing in the upper mids throughout the entire gain range of the pedal, and makes the pedal sound more amp-like and natural. Thick Switch: Provides a significant bass boost and simultaneous hi cut - this makes the pedal more suitable for bass guitar, lower tunings, as well as fattening up and smoothing low gain settings, making this a good candidate for overdrive use. 9-18v Operation: Increased headroom and fidelity with 18v operation and less "sagging" as compared to older Rats. Like all Rats, the FATRAT is a true bypass. Large CTS Pots give you a smooth, even sweep throughout their range.