The B-TRON III is a vintage envelope filter that creates a “Wah” or “vowel” sound every time you play a note. It includes three filter types via the Mode switch that includes low-, band-, or high-pass settings for a nice quack or a nice high-frequency sizzle. It works great for bringing the funk with either guitar, bass or keyboards. The Range switch on the B-TRON III can be toggled between low, so you can get more vowel-like sounds, or high to emphasize more overtones. And the Up and Down modes on the Drive switch can give you that traditional “Wah” sound or a cocked “Wow” sound.