Essentially three pedals in one housing, Cock Fight by Electro-Harmonix gives you two different kinds of wah (talk-wah and cry-wah) as well as fuzz distortion, and is suitable for both electric bass and electric guitar. Without an expression pedal, the unit acts as a fixed-position filter (or 'cocked-wah'), its 'freq' knob instantiating a specific frequency band for your guitar to pass through. However, if you plug in an external expression pedal (available separately) you'll be able to exert full domination over the frequency control with the rock of your foot, just like a standard wah pedal.  
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\r\nThe fuzz can be instantiated in series, either after the wah or before the wah—or you can bypass the fuzz entirely. Should you call upon the fuzz, the tone knob will allow you to blend between a darker sound and a brighter one. Also, a bias knob controls tonal characteristics related to the fuzz; crank it one way and you'll affect a 'normal' sound, but twist it in the other direction and you'll approximate a 'dying battery' effect.
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\r\nDon't discount the small bottom knob on the left the unit either—this one is particularly useful in conjunction with electric basses, as it can add some of the lows taken out by traditional bass-wahs back into the mix.