Darkglass do amazing stuff, and this fuzz is no exception. It's got two fuzz circuits, a squarewave gated style and a nasty hi gain style, blendable via the 'duality' control. The blend control adds your clean signal in to boot. The filter knob adjusts the highs and mids to find that spot in the mix you intend to disgustify to your liking. Finns winn again!

Model: Darkglass Duality Dual Fuzz Engine 
Made: Finland, recent model (serial AL82WV111)
Type: fuzz
Power: standard 9v negative power supply (not included)
Equivalent new street price (approx): $339aud
Mods: none
Accessories: no box or manual
Condition notes: used, no major marks, fully functional. Overall: excellent condition