Classic oldschool fuzz with adjustable momentary feedback switch.
Aimed at that elusive first-generation fuzz tone made most famous by Hendrix, in which at full guitar volume you get a sludgy, saturated, fluty, sustaining fuzz tone, and with the guitar volume turned down you get more of an overdrive sound. Step on the Scream switch for extra insanity.
The Skreddy Pedals™ Screaming Lizard is made from silicon transistors for stability, but it uses low gain units that can render germanium type fuzz tones.
The extra controls let you emulate different classic fuzz tones from the 60's and early 70's along with improvements for some of the issues those early fuzzes had (noise reduction, adjustable tone, and input impedance selector switch).
This can be a smooth saturated fuzz or an articulate fuzz, depending on how you set it up. The bias control is set up to give you just the right classic response at noon, and you can play with it to go harder or softer.
No special power requirements, just regular negative ground 9v.
Gives you a LOT more output volume than most classic fuzzes, with unity gain around noon and plenty of boost beyond that.
Lets you go from buzzy and low-fi to clear, louder, and more present. Sometimes referred to as a "MIDS" control since it does give you more (or less) of those too. Noon is the classic setting.
Lets you go from bright and articulate to smooth and syrupy with that lovely upper-harmonic emphasis you hear in classic fuzz recordings. It's really nothing more than an extra guitar tone control. This fuzz sounds so sweet with the tone rolled down that you will love having this dedicated control right where it's at, freeing up the guitar knobs for all your other applications.
Sets the gain for this whole thing. Most fuzzes of this type sound best with the fuzz turned either all the way up or dialled back just a touch from max (in my opinion). Gets milder and darker as you turn down.
HB / SC
Adds a bit of resistance to the input in order to keep a humbucker pickup from swamping the circuit and causing it to have a gated attack. But it's also useful for helping this fuzz work together with other effects (like to keep a wah pedal from making that siren sound you get from driving it into a vintage-style fuzz, or that extreme, trebly fuzz you get if you use a buffered pedal in front, for example).
Sets the amount of feedback you get when you hold down the corresponding footswitch