The Reeves Supa J dual fuzz is a circuit built by Reeves Electro, in the U.K., which combined a vintage Marshall Supa Fuzz and Jen Fuzz circuit into one incredible pedal. The Reeves pedal is no longer in production and was last selling for just under $700; the creator worked with Fuzzdog UK to create a circuit board so the circuit could be built by others who couldn't afford or didn't want to wait for an unspecified amount of time for a new pedal, and here we are!
The top toggle switch controls the voicing, either adding or removing low-mid frequencies which push the second transistor into a more saturated fuzz, while removing reduces bass and gain.
The bottom toggle switches between Marshall Supa Fuzz (LEFT) with no clipping diodes on the output, and Jen Fuzz (RIGHT), with clipping diodes on the output.
Nerdy stuff :
This circuit uses 2N2222A, BC108, and BC108C metal can transistors, as well as BAT46 clipping diodes.
Available in the silver Gorva enclosure with rounded corners,  or standard 125B enclosure in blue. 
Hand built using genuine, verified transistors, metal film resistors, high quality electrolytic capacitors, and a pro grade footswitch rated over 2x the life of standard switches. Bench tested prior to shipping, satisfaction guaranteed.