The Flex Drive is a very flexible pedal. The switches let you adjust treble, clipping, and fatness. This pedal is in mint condition. Here is some info from the website:
The most versatile overdrive of the entire line, the Flex Drive by J Rockett Audio Designs has a massive range of tone, all within the realms of timeless tone. It was originally designed to get the perfect Malcolm-esque rhythm tone yet can reach into Eddie’s arsenal for powerful, cutting leads as well. Its control setup is perfectly aligned to keep the footswitch free and the most-used dials comparatively larger for on-the-fly toe rolls. The volume, gain, and tone are all dead simple to dial in while a flip of the fat switch boosts the low end and midrange to give your signal a little extra beef. The treble switch is a three-way voicing control that cuts the highs in two different ways with the center acting as an unaffected EQ. Finally, to get a little extra tonal character, J Rockett has added a three-way clip voicing switch that initiates different sets of diodes to shape the sound with a bit of extra grit and crunch.